Geol  ogy 


The  Mineralogy  of  Arizona 


BY 


F.  N.  GUILD 

Professor  of  Chemistry  and  Mineralogy,  University  of  Arizona 


EASTON,  PA. 
THE  CHEMICAL  PUBLISHING  CO. 

1910 


LONDON,  ENGLAND: 

WILLIAMS  &  NORGATE 

14  HENRIETTA  STREET,  COVENT  GARDEN,  W.  D. 


COPYRIGHT,  1910,  BY  EDWARD  HART 


INTRODUCTION 

It  is  well  known  to  students  of  mineralogy  that  the  greater  num- 
ber of  interesting  minerals  are  found  at  some  depth  below  the 
surface  in  regions  where  the  destructive  effect  of  erosion  and  the 
decomposing  action  of  meteoric  water  are  not  active  and  hence  can 
be  reached  only  by  expensive  exploitation  rarely  undertaken  ex- 
cept when  compensation  is  hoped  for.  in  the  possible  discovery  of 
the  precious  or  useful  metals.  Arizona  is  attracting  considerable 
attention  on  account  of  its  unusual  mineral  resources,  and  its 
mountains  and  canons  are  filled  with  excavations  which  are  evi- 
dences of  the  enthusiasm  with  which  the  search  is  carried  on. 
Thus  formations  are  penetrated  and  minerals  exposed  to  view 
which,  lacking  this  incentive,  would  never  have  been  discovered. 

In  certain  respects  many  of  the  minerals  in  Arizona  are  suffi- 
ciently unusual  in  their  mode  of  occurrence  and  in  their  composi- 
tion to  warrant  special  attention.  The  rather  common  occurrence 
of  vanadium,  tungsten  and  molybdenum,  associated  with  deposits 
of  economic  value,  has  been  the  subject  of  frequent  mention  in  the 
scientific  journals.  These  are  of  great  interest,  not  only  from  the 
variety  and  beauty  of  the  crystallizations  presented,  but,  contain- 
ing as  they  do,  elements  of  considerable  rarity,  because  the  chem- 
ical and  geological  conditions  which  have  given  rise  to  them  de- 
mand investigation.  The  object  of  this  publication,  then,  is  to 
give  a  fairly  complete  description  of  Arizona's  minerals  with  some 
reference  to  their  mode  of  occurrence,  associations  and  chemical 
composition.  The  order  of  treatment  is  in  accordance  with  the 
well  known  classification  of  Dana.  The  elements  found  as  min- 
erals are  considered  first ;  then  the  sulphides  and  others,  as  out- 
lined in  the  following  table. 


819491 


CLASSIFICATION  AND  ORDER  OF  TREATMENT 

PAGE 

I.  Native  Elements 5 

II.  Sulphides,  Arsenides,  Etc 23 

III.  Sulpho-salts,  Sulpharsenites,  Etc.    31 

IV.  Chlorides,  Fluorides,  Bromides,  Etc. 33 

V.  Oxides    36 

VI.  Oxygen  Salts 46 

1 i)  Carbonates 46 

(2)  Silicates   56 

(3)  Phosphates,  Vanadates,  Etc 73 

(4)  Sulphates < 83 

(5)  Tungstates  and  Molybdates 92 

VII.  New  Minerals  Discovered  in  Arizona 97 


I.  NATIVE  ELEMENTS 


Diamond,  C 

Composition  and  Artificial  Production. — The  diamond 
is  crystallized  carbon  not  different  in  its  chemical  com- 
position from  pure  charcoal.  Because  of  the  simplicity 
of  its  composition,  attempts  have  repeatedly  been  made 
in  chemical  laboratories  to  produce  it.  The  method  of 
investigation  usually  consists  in  dissolving  carbon  in 
molton  iron  or  similar  media,  and  allowing  it  to  crystal- 
lize while  cooling.  Until  recently  all  such  attempts 
have  failed,  owing  to  the  habit  of  carbon  to  crystallize  in 
the  form  of  graphite  rather  than  in  its  other  possible 
form,  the  diamond.  Moisson,  however,  succeeded  in 
producing  the  diamond  by  heating  iron  in  which 
carbon  was  dissolved  to  a  temperature  of  3000  C.  by 
means  of  an  electric  furnace,  and  suddenly  cooling  the 
mass  by  plunging  it  into  cold  water.  By  this  simple 
method  a  cold  solid  shell  was  formed,  which  on  contract- 
ing, subjected  the  remaining  liquid  mass  to  enormous 
pressure.  Under  these  extraordinary  conditions  a  part 
of  the  carbon  crystallized  in  the  form  of  diamond. 
The  product,  however,  was  too  small  and  in  crystals  too 
imperfect  to  warrant  much  hope  that  by  this  means 
diamonds  of  sufficient  size  and  brilliancy  could  be  pro- 
duced to  serve  as  gems.1  These  investigations,  together 
with  the  researches  on  meteorites  described  below,  sug- 

i  Comptes  rendus  de  T Academic  des  Sciences.  116,  218. 


6  THE    MINERALOGY    OF    ARIZONA 

gest  a  possible  origin  of  the  gem  in  nature,  the  factors 
in  its  formation  being  a  solution  of  carbon  in  a  basic 
magma  and  high  pressure. 

Terrestrial  Diamond. — Although  diamonds  have  been 
found  in  many  of  the  states,  notably  in  North  Carolina, 
Virginia,  Oregon,  California  and  Wisconsin,  Arizona  has 
yet  to  report  an  authentic  discovery  of  this  valuable  gem 
mineral.  In  1870,  however,  a  company  was  organized 
for  the  exploitation  of  diamonds  and  other  gems  in 
Arizona  and  New  Mexico.  It  is  said  that  80,000  carats 
of  so-called  rubies  and  many  diamonds  purporting  to 
have  been  collected  from  these  fields,  were  displayed  to 
prospective  stock  buyers.  Expeditions  to  the  locality 
were  made,  and  in  a  week's  time  as  many  as  6,000  carats 
of  rubies  and  1,000  carats  of  diamonds  are  said  to  have 
been  gathered.  Finally,  Mr.  Clarence  King,  then  Direct- 
or of  the  United  States  Geological  Survey,  made  a  trip 
to  these  famous  gem  fields,  and  succeeded  in  bringing  to 
light  the  fact  that  an  American  had  actually  purchased 
in  London  a  large  quantity  of  rough  diamonds  with 
which  the  deposit  had  been  salted  ;  salted,  in  fact,  so 
thoroughly  that  an  occasional  diamond  was  picked  up  in 
this  district  even  several  years  after  the  event.1  The  in- 
cident is  well  characterized  by  Hintze  in  his  Handbuch 
der  Mineralogie  as  a  "  grossartige  Schwindel." 

Diamonds  are  most  frequently  associated  with  perido- 
tites,  serpentines  and  other  ultra-basic  rocks,  or  the 
debris  accompanying  such  rocks,  a  fact  that  should  be 
borne  in  mind  by  the  mineralogist  or  miner  while  search- 

1  Kunz  :  Gems,  p.  36. 


NATIVE    ELEMENTS  7 

ing  for  these  gems.  The  recent  discovery  of  diamonds 
in  Arkansas,  where  they  are  found  in  peridotitic  rock 
material  similar  to  the  South  African  fields,  is  a  good 
illustration  of  this  very  characteristic  mode  of  occurrence. 
These  types  of  rocks,  though  not  abundant  in  Arizona, 
are  present  in  certain  localities,  and  they  might  well  be 
the  subject  of  special  research  for  these  gems  as  well  as 
other  minerals  known  to  occur  associated  with  them. 

Meteoric  Diamond.— The  presence  of  crystallized  car- 
bon or  the  diamond  in  meteoric  iron  was  first  proved  by 
Jerofejew  and  Latschnow,  in  1888,  in  their  investigations 
of  the  meteor  which  fell  in  Nowo-Urei,  Krasnoslobodsk, 
Russia,  on  the  22d  day  of  September,  1886.  Since  that 
time  the  diamond  has  been  found  in  meteoric  iron  in 
widely  different  localities,  but  notably,  perhaps,  in  the 
Canon  Diablo  specimens  found  near  Coon  Mountain,  or 
Crater  Mountain,  in  the  northern  part  of  Arizona. 
Papers  on  the  subject  of  diamonds  in  these  meteoric 
masses  have  appeared  by  Foote  and  Koenig,1  by  Hunting- 
ton  and  Kunz,  by  Friedel,2  by  Cohen,  and  by  others. 
Moisson,  in  his  researches  on  the  artificial  production  of 
the  diamond  in  the  electric  furnace,  directed  special  at- 
tention to  the  occurrence  of  this  mineral  in  the  Arizona 
meteorites.  Some  of  the  crystals  obtained  by  him  meas- 
ured 0.7  by  0.3  millimeters.  They  were  yellow  in  tint, 
of  rough  surface,  and  transparent.3 

1  Am.  Jour.  Sci.,  1891,  43,  413. 

2  Bui.  Soc.  Min.,  Paris,  1892,  15,  285. 

*  Moisson  :  I<e  Four  IJlectrique,  p.  140. 


8  THE    MINERALOGY    OF    ARIZONA 

Graphite,  C 

So  far  as  the  writer  knows,  pure  graphite  has  not  been 
found  in  Arizona.  A  black,  graphite-like  clay  is  found 
in  large  quantities  near  Benson,  and  will  be  described 
under  Graphitic  Clay. 

Seams  of  what  appeared  to  be  impure  graphite  in  black 
carbon  shales  have  frequently  been  observed,  but  no 
analyses  have  been  made. 

Sulphur,  S 

Sulphur  has  been  found  in  very  small  quantities  in 
some  of  the  crater  cones  near  Sunset  Peak,  in  the  San 
Francisco  mountains  near  Flagstaff.  Abundant  silicious 
sinter  occurs  here,  showing  that  a  solfataric  period  fol- 
lowed the  more  active  stages  of  vulcanism.  The  sinter 
is  frequently  of  a  pure  sulphur  yellow  tint  and  has  been 
mistaken  by  many  tourists  for  sulphur. 

Arsenic,  As 

Attention  has  recently  been  called  to  an  interesting 
occurrence  of  this  element  in  Washington  Camp,  Santa 
Cruz  County.1  Here  it  occurs  in  reniform  masses,  some- 
times several  pounds  in  weight  attached  to  the  walls  of  a 
small  pocket  in  dolomitic  limestone.  The  latter  is  highly 
metamorphic  and  crossed  by  veins  carrying  lead,  copper 
and  zinc  minerals.  Intrusive  rocks  are  abundant  in  the 
district  and  are  considered  to  be  concerned  in  some  way 
with  the  mineralization  of  the  limestone.  The  action 
especially  concerned  with  the  deposition  of  the  arsenic  is 
supposed  to  be  fumerolic. 

1  C.  H.  Warren  :  Amer.  Jour.  Sci.,  4th  series,  16,  337. 


NATIVE)    ELEMENTS  9 

Gold,  Au 

As  is  well  known,  native  gold  occurs  in  many  localities 
in  Arizona  both  as  placer  deposits  and  vein  formations. 

Nuggets  of,  the  value  of  $400.00  each  have  been  taken 
from  the  Weaver  placers.1  Other  well  known  placers  are 
those  of  Graterville,  Canada  del  Oro  in  the  Catalina 
mountains,  L,inx  Creek  near  Prescott,  etc.  A  description 
of  these  deposits,  as  well  as  of  the  gold  veins  of  Arizona, 
would  appear  more  properly,  perhaps,  in  a  publication 
on  mines  than  in  one  on  mineralogy.  A  few  rather  in- 
teresting modes  of  occurrence  may,  however,  be  men- 
tioned. 

Native  Gold  in  Igneous  Rocks. — An  unusual  occurrence 
of  this  kind  was  recently  called  to  the  writers  attention 
by  Mr.  G.  W.  Maynard,  a  mining  engineer  of  New  York 
City.  The  gold  is  found  in  thin  paper-like  incrustations 
in  the  fine  cracks  of  a  rhyolitic  rock,  which  occurs  on 
the  northeast  slopes  of  the  Catalina  mountains,  near 
Tucson.  The  rock  is  somewhat  brecciated  in  places,  the 
fragments,  also  rhyolite  (felsite),  being  partially  digested 
by  the  magma.  The  rock,  when  crushed  and  panned, 
shows  a  distinct  color  of  gold,  but  analyses  never  give 
more  than  a  trace  of  the  precious  metal.  Mr.  G.  P. 
Merrill2  and  W.  P.  Blake3  have  described  the  occurrence 
of  gold  in  granite,  and  Mr.  Moericke*  its  occurrence  in  a 
trachitic  rock.  In  all  of  these  cases  the  gold  seems  to  be 

1  W.  P.  Blake  :  Rep  to  Gov.,  1899. 

2  Am.  Jour.  Sci.,  4th  series,  i,  p.  309. 

3  Am.  In.  Min.  Eng.,  26,  290. 

*  Tschermaks  :  Min.  u.  Pet.  Mit.,  Ill,  1891. 


IO  THE    MINERALOGY    OH    ARIZONA 

primary,  sometimes  embedded  and  even  completely  en- 
veloped in  crystals  of  quartz  and  feldspar.  In  the  rocks 
of  the  Catalina  mountains  it  would  seem  quite  probable 
that  the  gold  is  secondary,  having  been  deposited  in  the 
minute  cracks  by  percolating  solutions.  Quite  likely  the 
gold  originally  existed  in  the  eruptive  but  in  such  minute 
quantities  that  it  could  be  detected  only  after  the 
concentration  described  above  had  taken  place.  The 
writer  has  frequently  observed  similar  superficial  min- 
eralization along  joint  planes,  especially  in  the  case 
of  copper  where  the  country  rock  has  become  quite  deeply 
stained.  These  have  often  led  to  expensive  and  useless 
exploitations. 

Gold  in  Crystallized  Calcite. — Some  years  ago  a  small 
sample  of  vein  material  was  received  by  the  writer  from 
the  Vekol  mining  district  which  consisted  chiefly  of 
white  quartz  and  cleavage  masses  of  calcite.  Embedded 
in  the  latter  were  several  small  grains  of  gold  about  two 
millimeters  in  diameter.  It  might  at  first  seem  that  the 
gold  had  been  formed  by  the  same  processes  and  at  the 
same  time  as  the  calcite.  A  closer  inspection,  however, 
showed  that  the  grains  of  gold  were  in  reality  attached 
to  quartz  and  were  projecting  into  a  cavity,  which  later 
became  filled  with  the  enclosing  calcite. 

Gold  in  Cerussite. — This  unusual  mode  of  occurrence 
has  been  observed  in  specimens  from  Oro  Blanco.  One 
large  sample,  weighing  several  pounds  and  consisting  al- 
most entirely  of  cerussite,  was  found  to  contain  nearly 
one  ounce  of  gold  per  ton.  The  gold  was  in  a  very  fine- 


NATIVE  ELEMENTS  n 

ly  divided  state  and  could  rarely  be  seen  even  by  the  aid 
of  a  hand  lens.  The  association  being  so  intimate  in  this 
case  one  is  inclined  to  look  upon  the  gold  as  having  been 
deposited  at  the  same  time  and  under  identical  conditions 
as  the  carbonate,  although  it  is  usually  held  that  gold  is 
not  deposited  from  the  same  media  as  those  which  give  rise 
to  lead  minerals,  especially  lead  minerals  occurring  in  the 
oxidized  zone.  Even  where  lead  minerals  are  found  in 
the  same  deposit  as  gold,  the  gold  is  usually  either  in  the 
gangue  or  in  some  accessory  mineral.  This  is  well  illus- 
trated in  the  ores  from  the  Elkhart  mine,  near  Chloride, 
Mohave  Co. ,  Arizona.  The  chief  minerals  found  here 
are  quartz  gangue,  galena  and  pyrite,  and  the  ore  is 
worked  chiefly  for  its  values  in  gold  and  silver.  Silver 
is  found  to  accompany  the  galena  and  gold  the  iron 
pyrite. 

Silver,  Ag 

Native  silver  has  been  found  in  the  Silver  King  mine, 
Final  Co.,  and  in  small  quantities  associated  with  argen- 
tiferous ores,  in  other  mines  of  the  State. 

Copper,  Cu 

Native  copper  is  frequently  found  in  the  zone  of  oxide 
enrichment  in  many  of  the  copper  mines  of  the  State. 
It  is  especially  abundant  at  Bisbee,  in  the  Copper 
Queen  mines,  the  Shattuck,  and  others,  where  it  occurs 
in  sheets,  nodules  and  aborescent  growths  associated  with 
cuprite,  kaolin,  calcite,  limonite,  and  other  minerals.  It 
is  interesting  to  note  that  in  the  Holbrook  shaft,  espec- 
ially in  the  neighborhood  of  the  400  ft.  level,  the  ore 


12  THE    MINERALOGY    OF    ARIZONA 

lenses  contain  considerable  chalcocite.  These  have  fre- 
quently become  oxidized  only  on  their  margins.  This 
has  become  a  guide  to  the  miners,  and  when  striking  na- 
tive copper  after  driving  through  barren  ground,  they 
know  they  are  about  to  reach  a  rich  ore  shoot.  When 
they  are  in  ore  and  strike  native  copper  they  believe  that 
they  are  near  the  end  of  the  rich  deposit.  A  large  sample 
of  native  copper  presented  to  the  University,  by  Dr.  H. 
W.  Fenner,  of  Tucson,  shows  delicate  sponge-like  forms 
consisting  of  aborescent  masses  altered  superficially  to 
malachite.  Another  interesting  mode  of  occurrence  ob- 
served in  situ  by  the  mining  class  of  the  University  while 
on  one  of  its  annual  trips,  was  that  of  delicate  mosslike 
masses  containing  embedded  rhombs  of  calcite  of  almost 
perfect  development.  In  the  mines  of  Cananea,  Mexico, 
the  mode  of  occurrence  is  somewhat  different.  Here  the 
native  copper  is  found  in  thin  sheets  and  slabs  between 
the  fracture  planes  in  brecciated  quartzite,  and  is  not  so 
often  associated  with  the  other  enrichment  minerals  of 
copper. 

Native  Copper  in  Epidote. — Many  of  the  copper  deposits 
of  Arizona  are  in  a  contact  zone  associated  with  garnet, 
epidote,  and  other  minerals  characteristic  of  contact 
metamorphism.  It  is  not  often,  however,  that  the  min- 
erals of  copper,  and  especially  native  copper,  appear  in 
the  same  hand  specimen  as  the  contact  minerals  men- 
tioned above.  Samples  showing  this  intimate  association 
have  been  received  at  the  University  from  two  distinct 
localities,  one  from  the  northern  part  of  the  State, 


NATIVE    ELEMENTS  13 

the  exact  place  unknown,  and  the  other  from  the  Santa 
Rita  mountains,  south  of  Tucson.  The  two  samples 
were  almost  identical  in  appearance.  They  were  made 
up  of  hard,  compact  epidote  of  the  characteristic  yellow 
color,  and  in  places  contained  as  many  as  forty  or  fifty 
brilliant  grains  of  copper  to  one  square  inch  of  surface. 
These  vary  in  size  from  a  fraction  of  a  millimeter  to  two 
or  three  millimeters  in  diameter.  The  epidote  from  the 
Santa  Rita  locality  is  slightly  altered  by  the  infiltration 
of  both  calcite  and  silica.  It  may  be  possible  that  the 
presence  of  the  copper  is  due  to  the  same  secondary 
action. 

Native  Copper  in  a  Trap  Rock.— Although  this  mode 
of  occurrence  has  been  observed  only  in  case  of  a  dike 
found  in  Sonora,  Mexico,  it  is  considered  of  sufficient  in- 
terest at  this  point  to  warrant  a  brief  description.  The 
rock  is  found  near  Washington  Camp,  Arizona,  only  a 
few  hundred  feet  from  the  Mexican  line.  It  is  quite  un- 
decomposed  in  appearance.  Fresh  fractures  show  it  to 
be  a  dark  colored,  almost  black  eruptive,  presenting  in 
places  the  characteristic  orphitic  structure  of  the  diabases. 
The  rock  is  crossed  by  many  small  fracture  planes,  along 
which  remarkably  slight  alteration  has  taken  place.  Yet 
it  is  along  these  planes  that  the  copper  appears  as  thin 
paper-like  fillings  and  aborescent  incrustations,  giving 
the  surface  of  the  rock  as  it  is  broken  open  a  metallic, 
moss-like  appearance.  Under  the  petrographic  micro- 
scope, the  rock  is  found  to  be  a  quite  typical  diabase, 
with  orphitic  structure  fairly  well  developed,  with  the 


14  THE    MINERALOGY    OF    ARIZONA 

exception  that  the  feldspars  contain  numerous  and  re- 
markably large  inclusions  of  the  pyroxenes.  The  latter 
mineral  is  but  slightly  altered  to  chlorite,  while  the  feld- 
spars are  sufficiently  fresh  to  show  the  characteristic 
polysynthetic  twinning  of  the  plagioclases.  The  copper 
appears  as  small  bunches  and  in  thin  threads,  which 
sometimes  nearly  cross  the  field  of  the  microscope. 
These  are,  of  course,  cross  sections  of  the  fracture  planes 
mentioned  above.  The  threads  are  sometimes  not  more 
than  0.02  millimeters  in  width  and  several  millimeters  in 
length.  The  copper  has  evidently  been  brought  in  and 
deposited  by  solutions  which  have  not  materially  affected 
the  rock  through  which  they  passed.  The  metal  may 
have  been  derived  from  other  portions  of  the  dike,  or 
more  probably  from  other  mineralized  rocks  in  the 
vicinity. 

Platinum,  Pt 

Traces  of  this  metal  have  been  reported  by  the  United 
Geological  Survey,1  in  a  sample  of  black  sand  from  near 
Prescott,  and  in  another  sample  of  the  same  material  from 
near  Columbia.  At  the  University  of  Arizona  several 
samples  of  supposed  platinum  ore  have  been  investigated, 
but  always  with  negative  results. 

Iron,  Fe. 

Native  iron  is  not  often  found  as  an  original  con- 
stituent of  the  earth's  crust.  It  has  been  observed,  how- 
ever, in  nearly  every  part  of  the  world  in  the  form  of 
meteoric  iron.  These  fragments  are  simply  inter-planetary 

1  Mineral  Resources,  1905. 


NATIVE;  EI,EMENTS  15 

particles  which  the  earth  picks  up  during  its  journey 
through  space.  These  particles  have  been  seen  to  strike 
the  earth  and  having  been  examined  before  they  have 
had  time  to  become  cold,  there  is  no  doubt  as  to  their 
immediate  origin.  It  is  claimed1  that  during  every  24 
hours  the  earth  encounters  many  millions  of  these  frag- 
ments, and,  were  it  not  for  the  protecting  influence  of  our 
atmosphere,  the  vegetation  and  animal  life  would  soon 
be  destroyed  owing  to  the  continual  impact  of  these  mi- 
nute projectiles.  The  atmosphere  serves  as  a  protecting 
medium  through  which  these  minute  bodies  are  unable 
to  pass  without  becoming  thoroughly  disintegrated  into 
a  fine  dust, due  to  the  high  temperature  caused  by  friction. 
Though  very  few  of  them  ever  reach  the  earth  in  a 
compact  form,  yet  the  weight  of  our  planet  is  yearly  in- 
creasing at  the  rate  of  a  few  tons  as  a  result  of  these  ad- 
ditions. Indeed,  it  is  even  believed  by  many  geologists 
that  our  planet  and  the  other  heavenly  bodies  owe  their 
origin  to  this  source  rather  than  to  a  central  molten  or 
gaseous  mass  which  by  centrifugal  action  has  suc- 
cessively thrown  off  masses  that  have  developed  into 
planets,  moons,  etc. 

The  Tuscon  Meteorites. — Two  important  masses  of 
meteoric  iron  have  been  discovered  in  the  vicinity  of 
Tucson,  but  thoroughly  reliable  data  as  to  the  exact 
point  where  they  fell  seem  to  be  lacking.  The  majority 
of  the  reports  mention  the  Santa  Rita  mountains,  south 
of  Tucson,  as  the  original  locality,  while  a  few  author- 
ities refer  to  the  fall  as  having  taken  place  in  the  '  'Santa 

1  Todd  :  New  Astronomy,  p.  412. 


l6  THE    MINERALOGY    OF    ARIZONA 

Catarina"  mountains  north  of  Tucson.  The  fact  that 
Mexico  is  sometimes  mentioned  is  to  be  expected  since 
at  that  time  Tucson  and  vicinity  were  a  part  of  that 
country. 

According  to  Mr.  L,.  Fletcher1  the  attention   of   the 
scientific  world  was  first  called  to  these  meteorites  through 


Fig.  i.— The  Tucson  Ring  Meteorite  as  originally  seen  in  a  blacksmith 

shop  in  Tucson,  where  it  was  employed  as  an  anvil. 

(Drawn  by  Geo.  Nishihara  from  an  old  wood  cut  in  Bartlett's 

Explorations,  Vol.  II,  1854.) 

the  verbal  report  of  the  entomologist,  Dr.  J.  L,.  I,eConte 
of  Philadelphia,  at  a  meeting  of  the  American  Association 
for  the  Advancement  of  Science  held  at  Albany  in 
August,  1 85 1 .  He  reported  that '  'while  passing  through 
the  village  of  Tucson  in  the  proceeding  February,  he  had 
observed  two  large  pieces  of  meteoric  iron  used  by  the 

1  The  Meteoric  Iron  of  Tucson,  Mineralogical  Magazine,  9,  No.  41,  p.  16. 


NATIVE;  EI^MSNTS  17 

blacksmiths  of  the  town  as  anvils.'1  The  blacksmiths 
were  reported  as  having  been  very  persistent  in  not  al- 
lowing him  to  chip  off  fragments  for  further  examination 
stating  that  in  a  certain  canon  in  the  immediate  vicinity 
the  fragments  were  so  abundant  that  many  samples  could 
easily  be  obtained. 

In  1854,  Professor  Shepard1  gave  a  brief  account  of 
these  meteorites,  in  which  he  states  that  according  to  in- 
formations furnished  him,  they  were  found  in  a  canon 
of  the  Santa  Rita  mountains,  about  25  or  30  miles  south 
of  Tucson.  Both  were  reported  as  being  used  as  anvils, 
and  one  was  described  as  being  of  a  peculiar  annular 
form.  About  this  time  also,  samples  were  analyzed  by 
Professor  Lawrence  Smith2  and  others. 

In  1857,  Dr.  Irwin,  Surgeon  of  the  United  States 
Army,  found  the  ring  meteorite  in  one  of  the  streets  of 
Tucson  and  took  possession  of  it  with  the  intention  of 
placing  it  in  the  Smithsonian  Institution.  It  was  started 
on  its  journey  in  1860,  and  after  traveling  to  Guaymas, 
Mexico,  then  to  San  Francisco,  finally  reached  Washing- 
ton in  1863,  by  way  of  the  Isthmus  of  Panama.  Dr.  Irwin 
states  that  it  was  considered  by  the  inhabitants  of  Tucson 
at  that  time  to  have  come  from  the  '  'Catarina' '  mountains, 
and  further,  that  it  was  believed  a  meteoric  shower  had 
taken  place  there  about  200  years  ago.3  It  would  seem, 
however,  as  explained  by  Mr.  Fletcher,  that  the  term 
"Catarina"  was  loosely  applied,  and  that  Dr.  Irwin  was 
thus  misinformed  as  to  the  real  locality. 

1  Am.  Jour.  Sci.,  2d  series,  18,  p.  369. 

2  Am.  Tour.  Sci.,  2d  series,  19,  p.  161. 

8  Smithsonian  Report,  1863,  and  Fletcher  :  Min.  Mag.,  9,  No.  41. 


l8  THE    MINERALOGY    OF    ARIZONA 

The  dimensions  of  the  annular  meteorite,  or  Irwin 
Iron,  as  it  is  sometimes  called,  still  to  be  found  in  the 
Museum  at  Washington,  are  given  by  Whitney,  as 
follows  : 

Greatest  exterior  diameter 49  in. 

Least  exterior  diameter 38  in. 

Greatest  width  of  central  opening 26^  in. 

Least  width  of  central  opening 23  in. 

Greatest  thickness  at  right  angles  to  plane  of 

ring 10  in . 

Width  of  thickest  part  of  ring 17 j£  in. 

Width  of  narrowest  part 2^  in. 

Weight 1,400  Ibs. 

This  fragment  is  further  known  as  the  Tucson  Meteor- 
ite, the  Signet,  the  Ring  Meteorite,  the  Ainsa,  the 
Muchacho,  etc. 

The  other  fragment  from  Tucson  was  of  the  shape  of 
an  elongated  flattened  slab.  Its  length  was  49  inches, 
average  breadth  18  inches,  and  varying  in  thickness  from 
2  to  5  inches.  Its  weight  was  determined  to  be  632  Ibs.1 
It  was  taken  possession  of  by  Gen.  Carleton  and  sent  to 
San  Francisco.  Hence  it  is  known  in  Mineralogical  liter- 
ature as  the  Carleton  Meteorite. 

As  a  result  of  the  investigations  on  polished  surfaces 
of  these  two  meteoric  masses,  it  is  generally  believed 
that  they  were  portions  of  the  same  mass,  or  at  least  both 
were  members  of  the  same  meteoric  shower. 

The  chemical  composition  is  illustrated  by  the  follow- 
ing analyses  : 2 

1  Proc.  Cal.  Ac.  Nat.  Sci.,  1863,  3,  pt.  i,  p.  49. 

2  Quoted  from  Min.  Mag.,  9,  No.  41. 


NATIVE    ELEMENTS  IQ 

Smith  Genth  Brush 

Per  cent.         Per  cent.         Per  cent. 

Fe    85.54  83.47  81.65 

Ni 8.55  9.44  9-17 

Co    0.61  0.42  0.44 

Cu    0.03  0.008  0.08 

P 0.12  o.io  0.49 

A12O3 Trace  Trace           Trace 

CaO 0.46  1.16 

MgO 2.04  2.59  243 

Cr2O3 0.21 

SiO2 3.02  2.89  2.63 

From  these  analyses  it  appears  that  the  meteorites  are 
mostly  nickel  iron,  with  small  quantities  of  olivine, 
schreibersite  and  chromite. 

An  excellent  model  of  the  ring  meteorite  has  recently 
(July,  1907),  been  received  from  Washington,  and  can 
be  seen  at  the  Museum  of  the  University  of  Arizona. 

Canon  Diablo  Iron. — One  of  the  most  famous  occur- 
rences of  meteoric  iron  in  the  world  is  that  of  the  Canon 
Diablo  iron,  found  in  the  immediate  vicinity  of  a  slight 
elevation,  variously  known  as  Crater  Mountain,  Coon 
Butte,  and  Meteor  Mountain.  It  is  located  in  the 
plateau  region  of  Arizona,  about  twelve  miles  from  the 
Santa  Fe  station,  known  as  Canon  Diablo,  and  thirty-five 
miles  from  Flagstaff.  The  iron  is  found  in  fragments 
scattered  on  the  surface  of  the  ground  in  sizes  varying 
from  that  of  a  bean  to  masses  weighing  over  one  hundred 
pounds.  In  all  it  is  said  that  nearly  twenty  tons  of  the 
material  have  been  gathered  and  distributed  to  various 
museums  and  private  collections  in  all  parts  of  the  world. 
Occasionally,  as  many  as  thirty  fragments  may  be  picked 


2O  THE    MINERALOGY    OF    ARIZONA 

up  by  one  person  in  a  single  day.  They  are  especially 
easy  to  find  immediately  after  a  rain,  for  then  the  loose 
dirt  is  washed  away  from  the  fragments,  rendering  them 
more  easily  visible.  The  writer  visited  the  locality  in 
1906,  and  a  search  of  twenty  minutes  only  was  necessary 
in  order  to  secure  a  specimen  about  two  inches  in  length. 
At  the  station  of  Canon  Diablo  there  were  nine  large 
fragments  awaiting  shipment,  weighing  from  75  to  150 
Ibs.  each,  besides  several  large  boxes  containing  smaller 
pieces. 

The  locality  is  especially  interesting  to  the  geologist, 
not  only  on  account  of  the  meteoric  masses  found  there, 
but  because  of  the  interesting  question  as  to  the  origin 
of  the  elevation  apparently  so  intimately  connected  with 
them.  The  mountain  or  hill  contains  on  its  summit  a 
well  defined  depression  or  crater  which  has  a  maximum 
depth  of  600  feet,  and  a  width  of  3,500  feet.  The  walls 
of  the  crater,  which  are  quite  precipitous  in  places,  are 
formed  by  the  same  strata  of  sandstone  and  limestone  as 
those  which  make  up  the  floor  of  the  plateau.  These  are 
tilted  and  slope  away  from  the  cavity,  just  as  one  would  ex- 
pect, had  the  strata  been  uplifted  by  some  great  force  act- 
ing from  below,  followed  by  a  collapse  of  the  central  mass- 
There  is,  however,  an  entire  absence  of  fused  material  or 
volcanic  ejectamenta,  and  no  evidence  of  metamorphism 
of  an  igneous  character  having  taken  place  within  a 
radius  of  twelve  miles.  In  this  respect,  the  crater  is  un- 
like those  usually  found  in  a  volcanic  region.  This  fact, 
together  with  the  extraordinary  occurrence  of  meteoric 


NATIVE    ELEMENTS  21 

iron,  has  led  to  the  supposition  by  many  that  the  depres- 
sion was  not  caused  by  volcanic  action,  but  by  the  impact 
of  an  immense  meteor  nearly  one-half  mile  in  diameter, 
which  on  striking  the  earth  buried  itself  and  formed  up- 
turned edges  very  much  as  when  a  bullet  falls  into  soft 
mud.  Others  look  upon  the  phenomenon  as  having  been 
caused  by  a  volcanic  explosion  which  lacked  energy  suf- 
ficient to  bring  the  fused  mass  to  the  surface.  The  ex- 
plosion was  followed,  it  is  supposed,  by  a  complete  ces- 
sation of  vulcanism.  This  seems  to  be  the  better  explan- 
ation, since  it  can  easily  be  seen  that  such  an  explosion 
might  occur  on  the  border  of  a  region  of  such  extreme 
volcanic  activity  as  was  able  to  produce  the  most  lofty 
mountain  in  Arizona  as  well  as  more  than  a  hundred 
small  cinder  cones.1  Dr.  Chamberlin  of  Chicago  Univer- 
sity looks  upon  the  formation  as  having  been  produced 
by  an  explosion,  due  to  the  vaporization  of  underground 
water,  brought  about  by  the  near  approach  of  molten 
rock. 

Further,  there  seems  to  be  some  doubt  on  the  part  of 
some  regarding  the  meteoric  origin  of  the  iron  frag- 
ments. Dr.  Karl  Hintze,  in  his  Handbuch  der  Min- 
eralogie,  refers  to  the  Canon  Diablo  irons  as  possi- 
bly of  terrestrial  origin  ("  terrestrisch  vielleicht  " ) . 
H.  Moissan  also  makes  the  statement,  "  Ce  fer 
de  Canon  Diablo  a  e*te  regarde  par  certains  ge*ol- 
ogues  comme  une  meteorite,  et  par  d'autres  comme 

1  Coon  Mountain  and  its  Crater,  D.  M.  Barringer  :  Proc.  Ac.  Nat.  Sc.,  Dec., 
1905 ;  Coon  Butte,  Arizona,  B.  C.  Tilgham  ;  Ibid,  Coon  Mountain  Crater,  F.  N. 
Guild  :  Science,  26,  p.  24. 


22  THE    MINERALOGY    OF    ARIZONA 

un  fer  terrestre  analogue  au  fer  d'Ovifak  decouvert  au 
Greenland  par  Nordenskiold."  l 

The  composition  of  the  iron,  as  shown  by  the  follow- 
ing analyses  made  by  H.  Moisson,  of  Paris,  varies  greatly 
in  different  parts  of  the  same  fragment. 

1234 

Per  cent.         Per  cent.         Per  cent.         Per  cent. 

Iron 91.12  95.06  91.09  92.08 

Nickel 3.07  5.07  i. 08  7.05 

Small  quantities  of  silica,  magnesia  and  phosphorus 
are  also  reported. 

The  Weaver  Meteorite. — This  large  meteoric  fragment 
was  found  in  the  Weaver  mountains,  near  Wickenberg, 
Maricopa  Co.,  in  1898.  It  is  of  especial  interest  on 
account  of  its  high  percentage  of  nickel  and  cobalt  and 
its  uniformity  of  texture,  etching  solutions  failing  to 
bring  out  any  very  characteristic  figures.  The  locality 
in  which  it  was  found  has  yielded  but  one  fragment  of 
rounded  outline,  weighing  about  eighty  pounds.  Two 
analyses  of  this  meteorite  have  been  made  in  the  writer's 
laboratory  by  Mr.  W.  B.  Alexander  and  Mr.  F.  Hawley. 
The  results  are  shown  in  the  table  below. 

Alexander  Hawley 

Iron 79.60  81.81 

Nickel    18.80  16.63 

Cobalt i. 60  1.18 

Carbon,  manganese,  and  phosphorus. .  Traces  Traces 

Specific  gravity 7.9818  7.987 

The  meteorite  was  furthur  investigated  spectroscopi- 
cally  for  helium,  but  with  negative  results. 

i  Trait^  de  Chimie  Mineral,  Vol.  2,  p.  192. 


II.  SULPHIDES,  ARSENIDES,  ETC. 


Tetradymite,  Bi2(Te,S)3 

This  is  a  soft,  steel-gray  mineral  consisting  of  bismuth, 
sulphur  and  tellurium.  It  has  been  found  in  small  quan- 
tities in  the  Montgomery  Mine.1  It  also  occcurs  in 
quartz  associated  with  pyrite  near  Bradshaw  City, 
Yavapai  Co.,  where  it  is  found  slightly  altered  to  a 
brownish  decomposition  product,  probably  Montanite, 
the  bismuth  tellurate.2  This  mineral  frequently  contains 
gold,  and  is  often  associated  with  that  metal  in  the  tel- 
luride  ores  of  Colorado  and  California. 

Molybdenite,  MoS2 

This  is  a  soft  mineral,  closely  resembling  graphite  in 
its  general  appearance.  It  contains  sulphur  and  the 
semi-metal  molybdenum.  The  mineral  seems  to  be  quite 
widely  distributed  in  Arizona,  where  it  is  frequently 
found  as  an  accessory  in  many  of  the  copper,  lead  and 
silver  deposits.  In  the  Morenci  fissure  vein,  it  occurs 
in  primary  association  with  pyrite,  chalcopyrite  and  zinc 
blende.  It  is  also  present  in  the  ordinary  smelting  ore 
of  the  district,  as  shown  by  chemical  analysis.3 

In  the  Santa  Rita  mountains,  30  miles  south  of 
Tucson,  it  is  found  in  the  form  of  small  foliated  aggre- 

1  Dana  :  Text  Book  of  Mineralogy,  p.  285. 

2  Genth :  Am.  Jour.  Sci.,  3d  series,  40,  p.  114. 

3  L,indgren  :  U.  S.  G.  S.,  PP.  No.  43,  p.  107. 


24  THE;  MINERALOGY  OF  ARIZONA 

gates  in  pure  milky  quartz,  where  it  alters  to  molybdite, 
or  the  hydrous  ferric  molybdate.1 

In  the  Silver  Bell  district,  northwest  of  Tucson,  it 
occurs  in  large  masses,  sometimes  of  three  or  four  pounds 
weight,  consisting  of  crystalline  aggregates,  and  asso- 
ciated in  the  same  hand  specimen,  with  quartz,  galena, 
pyrite  and  chalcopyrite.  It  has  further  been  observed 
associated  with  secondary  sulphides  of  copper  in  the 
mines  at  Johnson,  near  Cochise. 

Domeykite,  Cu3As 

This  is  a  rare  arsenide  of  copper  usually  presenting  a 
tin-white  lustre,  easily  tarnishing  to  a  dull  bronze.  It 
is  very  tough  and  somewhat  malleable  under  the  ham- 
mer. Good  specimens  of  this  mineral  have  been  received 
at  the  University  of  Arizona  from  Cochise  County,  but 
no  data  regarding  the  associations  and  mode  of  occur- 
rence have  been  obtained. 

Argentite,  Silver  Glance,  Ag2S 

This  is  a  dark  lead-gray  mineral  resembling  copper 
glance  but  easily  distinguished  from  it  by  its  being  more 
easily  cut  with  a  knife.  It  has  been  reported  from  the 
Silver  King  mine,  and  is  occasionally  met  with  as  an  ac- 
cessory in  other  metalliferous  deposits  of  the  State. 
It  is  further  a  quite  constant  constituent  in  argen- 
tiferous galena  but  is  so  intimately  mixed  with  it  as  to 
escape  observation. 

i  Guild  :  Am.  Jour.  Sci.,  23,  p.  455. 


SULPHIDES,  ARSENIDES,  ETC.  2$ 

Hessite,  Ag2Te 

This  is  a  rare  telluride  of  silver  with  nearly  always 
some  gold.  It  has  been  reported  from  the  West  Side 
mine,  Tombstone.1 

Galena,  Lead  Glance,  PbS 

This  well  known  mineral  is  widely  distributed  in  the 
State,  as  is  shown  by  the  official  reports  on  the  pro- 
duction of  lead  from  the  different  counties.  In  all  about 
five  millions  of  pounds  of  the  metal  were  produced  in 
1905,  the  greater  portion  of  which  was  obtained  from 
this  mineral.  The  following  counties  were  represented  : 
Cochise,  Graham,  Mohave,  Pima,  Final,  Santa  Cruz, 
Yavapai  and  Yuma.2  The  frequent  occurrence  of  this 
mineral  with  gold  has  been  mentioned  by  W.  P.  Blake.3 
It  is  frequently  found  associated  with  the  oxidized 
products  of  lead  such  asanglesite,  cerussite,  etc.,  and  also 
with  wulfenite,  vanadinite,  decloizite,  etc.  The  localities 
and  different  modes  of  occurrence  are  too  numerous  to 
mention. 

Chalcocite,  Copper  Glance,  Cu2S 

This  also  is  a  well  known  mineral  usually  found  in  the 
zone  of  secondary  sulphide  enrichment  where  percolating 
copper  solutions  have  come  in  contact  with  lean  sulphides. 
It  is  especially  abundant  in  the  Clifton-Morenci  dis- 
trict where  it  is  found  in  disseminated  grains  and  seams 
in  altered  porphyries.  It  is  not  a  primary  mineral  here  as 

1  Hintze  :  Mineralogie,  p.  453. 

2  Mineral  Resources,  1905.  p.  138. 

3  Rep.  to  Gov.  of  Ariz.,  1899,  p.  105. 


26  THE)    MINERALOGY    OF    ARIZONA 

supposed  by  some,  but  has  been  formed  by  the  replace- 
ment processes  taken  place  between  grains  of  pyrite  or 
chalcopyrite  and  descending  copper  solutions.1 

In  the  Copper  Queen  mine  at  Bisbee  it  is  only  occasion- 
ally found,  where  it  is  described  as  an  envelope  on  pyrite 
showing  the  first  stages  of  a  secondary  enrichment 
process.2 

Stromeyerite,  Ag2S,  Cu2S. 

This  mineral  can  hardly  be  distinguished  from  copper 
glance  except  by  chemical  analysis.  The  essential  differ- 
ence consists  in  the  large  percentage  of  silver.  It  has 
been  observed  in  the  Heintzelman  mine,8  and  in  the  Silver 
King  mine,  Final  Co. 

Sphalerite,  ZnS. 

This  mineral  is  a  sulphide  of  zinc  and  varies  in  color 
from  yellow  and  almost  white,  through  orange  tints  to 
black.  When  pure,  it  has  a  characteristic  resin-like 
luster.  The  darker  varieties  owe  their  color  to  the 
sulphide  of  iron,  which  is  present  as  an  impurity.  These 
dark  modifications  are  frequently  called  by  the  miners 
black  jack  or  mock  lead  ;  the  purer  samples  are  referred 
to  as  rosin  jack. 

Sphalerite  has  been  frequently  found  as  an  accessory 
ore  in  many  of  the  mines  of  the  State,  associated 
with  argentiferous  galena,  pyrite  and  chalcopyrite.  It 
has  been  noted  below  the  zone  of  secondary  enrichment 
in  the  Clifton-Morenci  district,  disseminated  in  hard 

i  Lindgren  :  U.  S.  G.  SM  PP.  No.  43- 

«  U.  G.  S.,  PP.  No.  21,  p.  128. 

8  Dana  :  Text  Book  of  Mineralogy,  p.  290. 


SULPHIDES,  ARSENIDES,  ETC.  27 

limestone  and  metamorphic  rock.1  It  is  found  in  the 
silver-lead  prospects  in  the  San  Xavier  district,  asso- 
ciated with  galena  and  other  sulphides.  Small  quantities 
have  been  reported  from  the  copper  deposits  of  the  Hoi- 
brook  and  Gardiner  shafts,2  Bisbee.  In  the  Silver  King 
it  has  been  observed  as  occurring  in  light  sea-green 
masses,  associated  with  threads  of  native  silver,  which 
sometimes  cement  the  cleavage  masses  together.3  It 
further  occurs  below  oxidized  gold  ores  in  the  Montana 
mine  of  the  Oro  Blanco  district,  Santa  Cruz  Co.  The 
disastrous  effect  of  passing  from  free-milling  gold  or 
silver  ores  into  these  basic  sulphides  is  well  known. 

Zinc  of  commercial  importance  has  been  produced  by 
the  Copper  King  Mines  Co.,  operating  in  the  Tiger  dis- 
trict of  Yavapai  County.4 

Alabandite,  MnS 

This  rare  sulphide  is  quite  abundant  in  the  lyucky 
Cuss  mine  at  Tombstone  ;  it  is  usually  associated  with 
manganiferous  limestone,  in  both  massive  forms  and 
specimens  possessing  good  cubic  cleavage.  It  is  dull 
black  in  color  and  can  easily  be  recognized  from  the  fact 
that  it  gives  a  dark  green  streak  or  powder. 
Cinnabar,  HgS 

The  red  sulphide  of  mercury  is  found  in  Yuma  Co. ,  on 
the  properties  of  the  Colonial  Mining  Co.,  14  miles  from 
Ehrenberg.  The  ore  is  said  to  average  about  i}4  per 

1  Ijndgren  :  U.  S.  G.  S.,  PP.  No.  43. 

2  Ransome  :  U.  S.  G.  S.,  PP.  No.  21. 

3  W.  P.  Blake  :  Rep.  to  Gov.,  1899. 
*  Min.  Res.  of  the  U.  S.,  1905. 


28  THE;    MINERALOGY    OF    ARIZONA 

cent,  of  mercury.     The  same  mineral   has  also  been  re- 
ported from  Yavapai  County.1 

Covellite,  CuS 

This  is  an  indigo  blue  sulphide  of  copper,  frequently 
met  with  in  the  Butte  mining  district,  Montana,  but  very 
rare  elsewhere.  It  has  never  been  found  in  good  speci- 
mens in  Arizona,  and,  in  fact,  has  been  noted  only  in  the 
Ryerson  and  Montezuma  mines  in  the  Clifton- Morenci 
districts.2 

Bornite,  3Cu2S.Fe2S3 

This  beautiful  sulphide  of  copper  and  iron  can  easily 
be  recognized  from  its  striking  iridescent  tarnish,  for 
which  reason  it  is  frequently  called  variegated  copper  ore, 
or  peacock  ore.  The  colors  vary  in  the  same  hand  speci- 
men from  golden  yellow  and  greenish  tints  to  rich  brown 
and  purple.  It  is  nearly  always  associated  with  pyrite 
and  the  various  sulphides  of  copper. 

Bornite  is  frequently  met  with  in  the  zone  of  sulphide 
enrichment  in  the  Bisbee  district  and  in  other  copper 
deposits  of  the  State. 

Chalcopyrite,  Cu2S.Fe2S8 

This  mineral  is  known  as  copper  pyrites  and  can  be 
distinguished  from  iron  pyrites  which  it  closely  resembles 
in  its  inferior  hardness  and  usually  by  its  duller  and  more 
brass-like  luster.  It  occurs  in  the  Copper  Queen  mine, 
especially  in  the  lower  levels  where  frequently  large 
bodies  are  encountered,  is  less  abundant  in  the  Clifton- 

1  Min.  Res.  of  U.  S.,  1905,  p.  398. 
«  Lindgren  :  U.  S.  G.  S.,  PP.  No.  43. 


SULPHIDES,   ARSENIDES,  ETC.  2O, 

Morenci  district,  but  constitutes  the  chief  ore  in  the 
Jerome,  Silver  Bell,  Twin  Buttes,  Helvetia  and  other 
properties. 

Chalcopyrite  is  probably  the  mineral  in  which  the  cop- 
per in  many,  if  not  all,  of  the  mines  of  the  State 
originally  existed.  It  was  probably  mixed  with  large 
proportions  of  iron  pyrites,  and  might  in  most  cases 
more  appropriately  be  called  cuperiferous  iron  pyrites. 
The  other  minerals  have  been  derived  from  it  by  what  is 
known  as  metasomatic  or  replacement  processes.  This 
goes  on  very  much  as  follows :  The  lean  sulphide,  chalco- 
pyrite  or,  as  suggested  above,  iron  pyrites  which  contain 
a  small  amount  of  this  mineral,  on  being  exposed  to  the 
action  of  air  and  water,  becomes  oxidized,  setting  free 
among  other  constituents  copper  sulphate,  which  is  solu- 
ble in  water.  This  solution  descends,  and  coming  in 
contact  with  the  lean  sulphides  below,  a  replacement 
takes  place  by  which  copper  is  deposited  in  the  molecule 
and  iron  removed.1  The  deposit  is  then  called  an  enrich- 
ment zone,  and  such  sulphides  asbornite,  chalcocite,  etc., 
result. 

Pyrite,  FeS2 

This  mineral  is  so  well  known  on  account  of  its  wide 
distribution  that  no  extended  account  of  its  occurrence  in 
Arizona  is  necessary.  It  is  found  as  a  microscopic  ac- 
cessory mineral  in  many  of  the  igneous  rocks,  especially 
the  basic  dikes,  and  as  an  association  in  the  copper,  lead 
and  other  metalliferous  deposits,  including  gold  bearing 

i  See  Chalcocite,  where  a  first  stage  of  this  process  is  mentioned. 


3O  THE    MINERALOGY    OF    ARIZONA 

veins.  In  the  latter  case  it  is  not  unusually  present  near 
the  surface,  having  been  oxidized  to  limonite  or  hematite, 
thus  giving  the  rock  a  rusty  honey-combed  appearance. 
This  part  of  the  vein  material  is  called  "  free-milling, " 
since  the  pyrite  which  originally  held  the  gold  enclosed 
in  its  firm  crystalline  structure,  has  become  disintegrated, 
setting  *  '  free  ' '  the  gold  which  can  then  be  easily  ex- 
tracted by  well  known  metallurgical  processes. 

Schreibersite,  (Fe,  Ni,  Co)3P 

The  mineral  is  a  phosphide  of  iron  with  some  nickel 
and  cobalt.  It  occurs  only  in  meteorites,  and  has  been 
reported  from  the  Canon  Diablo  irons.1 

Cobaltite,  CoAsS 

Cobalt  ores,  presumably  of  economic  value,  have  re- 
cently been  discovered  in  the  vicinity  of  Jerome.  The 
minerals  have  not  been  thoroughly  investigated  yet,  but 
cobaltite,  associated  with  erythrite,  or  cobalt  bloom,  has 
been  positively  identified.2 

Cohenite,  Fe8C 

As  a'  mineral,  this  compound  has  been  found  only 
in  meteoric  iron.  It  is  a  carbide  of  iron,  as  the  formula 
given  above  indicates,  and  analyses  from  material  isolated 
from  the  Canon  Diablo  irons,  have  been  reported  by 
Derby.8 

1  Derby  :  Am.  Jour.  Sci.,  1895,  49,  107. 

2  See  Erythrite. 

*  Am.  Jour.  Sci.,  1895,  49,  106. 


ID.  SULPHO-SALTS,  SULPHARSENITES,  ETC 


Bournonite,  (Pb,  Cu2)3S.Sb2S3 

This  rather  rare  mineral  has  been  described  by  Profess- 
or W.  P.  Blake  as  associated  with  pyrite,  sphalerite  and 
galena  at  the  Boggs  mine,  in  the  Big  Bug  district.1  It 
is  a  soft,  easily  fusible  dark  steel-gray  mineral,  possessing 
the  chemical  composition  of  a  sulphantimonate  of  lead 
and  copper. 

Tetrahedrite,  or  Gray  Copper,  Cu8Sb2S7 

This  is  a  sulphantimonite  of  copper  with  varying 
amounts  of  the  metal  replaced  by  silver,  lead,  zinc,  etc. 
It  more  often  accompanies  silver  ores  than  copper.  In 
Arizona  it  occurs  in  the  Heintzelman  mine  and  the  Silver 
King,  Pinal  Co.,  where  assays  have  run  as  high  as  3,000 
ounces  silver  to  the  ton.2 

Pyrargyrite  and  Proustite,  or  Ruby  Silver  Ores 
Ag3SbS3,  and  Ag3AsS3 

These  rare  minerals  are  the  sulphantimonites  and 
sulpharsenites  of  silver.  They  have  occasionally  been 
met  with  accompanying  other  silver  ores  in  many  of  the 
ore  deposits  of  the  State.  (Dana.)  When  first  taken 
from  the  mine  they  possess  a  beautiful  pure  ruby  color. 
Unfortunately,  however,  on  exposure  to  light,  they 

1  Am.  Jour.  Sci.,  3d  series,  39,  p.  45. 

2  W.  P.  Blake  :  Report  of  Ter.  Geologist,  1909. 


32  THE    MINERALOGY    OF    ARIZONA 

darken  and  finally  become  dull  black.  The  beautiful 
masses  from  Mexico,  preserved  in  the  British  Museum, 
have  kept  their  ruby  aspect,  having  been  enclosed  in 
black  boxes. 

Polybasite,  Ag9SbS6 

This  is  another  rare  sulphantimonite  of  silver,  differ- 
ing from  ruby  silver,  in  containing  a  larger  percentage 
of  silver.  It  has  been  observed  in  the  Silver  King  mine. 
(Dana.) 


IV.  CHLORIDES,  FLUORIDES,  BROMIDES,  ETC. 


Halite,  Common  Salt,  NaCl 

This  mineral  is  found  dissolved  in  the  water  of  all 
streams,  springs  and  underground  sources,  but  ordinarily 
in  such  small  quantities  as  to  be  hardly  perceptible  except 
by  chemical  analysis.  It  has  been  found  in  beautiful 
transparent  masses  associated  with  thenardite,  mirabilite 
andglauberite  in  the  Verde  Valley,  Yavapai  Co.,  where  it 
appears  in  irregular  deposits  in  the  more  abundant  sul- 
phates mentioned  above.  The  deposit  has  resulted  from 
the  evaporation  of  an  inland  sea  or  lake.1  This  mineral 
is  further  found  in  salt  springs  in  the  upper  Salt  River 
Valley. 

Cerargyrite,  or  Horn  Silver,  AgCl 

Horn  silver,  the  miner's  name  for  the  chloride  and 
bromo-chloride  of  silver,  can  be  easily  recognized  from 
its  waxy  appearance,  and  from  the  fact  that  it  can  be  cut 
with  a  knife  into  thin  shavings  which  do  not  fall  apart. 
It  has  been  frequently  observed  in  the  zone  of  oxidation 
in  many  of  the  silver  deposits  of  the  State.  It  has 
been  reported  in  the  following  districts  :  Tyndall,  Santa 
Cruz  Co.,  Cerro  Colorado,  Black  Warrior  and  others. 

Embolite,  Ag(Cl,  Br) 

This  mineral  is  very  similar  to  the  one  mentioned  above, 
usually  occurring  in  greenish  waxy  grains,  disseminated 

i  W.  P.  Blake  :  Am.  Jour.  Sci.,  3d  series,  39,  p.  44, 


34  THE    MINERALOGY    OF    ARIZONA 

through  the  vein  material.     It  is  especially  abundant  in 
the  Pearce  mining  district. 

lodobromite,  Ag(Br,  I) 

This  mineral  resembles  embolite  in  chemical  composi- 
tion, but  has  its  chlorine  replaced  by  iodine.  The  mineral 
is  extremely  rare,  but  has  been  reported  from  the  Hech- 
man  mine,  near  Globe,  by  Professor  W.  P.  Blake.1  It 
appears  as  a  bright  yellow  to  pale  greenish  thin  incrusta- 
tion in  veins  of  quartz  and  calcite. 

lodyrite,  Agl 

This  is  another  very  rare  mineral  of  silver  appearing 
in  almost  identical  forms  with  the  proceeding.  It  has 
been  found  in  the  Cerro  Colorado  mines. 

Fluorite,  or  Fluospar,  CaFl2 

Fluospar  is  a  well  known  mineral,  occurring  in  a  great 
variety  of  colors,  purple,  green,  pink  and  white  being  the 
most  common.  It  is  easily  recognized  by  its  hardness  and 
octahedral  cleavage, breaking  up  into  small  pieces  with  tri- 
angular surfaces.  It  is  a  quite  common  gangue  mineral 
in  metalliferous  deposits,  especially  found  associated  with 
lead  ores.  In  the  mines  of  the  Silver  Bell  district,  it  oc- 
curs in  green  cubes  with  barite,  galena  and  chalcopyrite. 
In  the  Castle  Dome  district  north  of  Yuma,  it  is  found 
associated  with  galena,  vanadinite,  and  minerals  of  silver. 
In  the  Dragoon  mountains  it  is  found  in  small  quantities 
in  very  acid  pegmatites  associated  with  huebnerite.  It 
has  also  been  observed  in  the  coarse  unmineralized  gran- 

i  Am.  Jour.  Sci.,  4th  series,  19,  p.  230. 


CHLORIDES,  FLUORIDES,  BROMIDES,  ETC.  35 

ites  at  the  Laguna  dam  on  the  Colorado  river.  Small 
quantities  of  this  mineral  have  been  produced  commer- 
cially in  Arizona  and  have  sold  at  prices  as  high  as  $i  1.50 
per  ton.1 

Atacamite,  Cu2Cl(OH)3 

This  mineral  which  is  a  rare  hydrous  chloride  of  cop- 
per has  been  found  only  in  very  small  quantities  in  the 
United  Verde  mine,  at  Jerome,  and  in  the  Heintzelmann 
mine.  A  similar  mineral  called  Footeite  has  been  de- 
scribed from  the  Copper  Queen  mines  at  Bisbee.  (Koenig) . 

i  Min.  Res.,  1903. 


V.  OXIDES 


Quartz,  Si02 

Quartz  is  the  most  common  of  minerals,  occurring  as 
sand,  gravel,  sandstone,  quartzite,  flint,  chalcedony, 
agate,  as  constituent  of  granite,  quartzporphyries,  etc. 

Sandstone. — A  beautiful  red  sandstone  has  been  quite 
extensively  worked  near  Flagstaff  and  widely  used  as  an 
ornamental  building  stone.  It  is  rather  soft  and  does  not 
stand  well  the  action  of  frost  and  moisture. 

Chalcedony. — This  variety  of  quartz  is  wax-like  in 
appearance,  translucent  and  of  uniform  color.  The 
various  colors  are  given  different  names ;  for  example, 
red  samples  are  termed  carnelian,  green  varieties  prase 
and  chrysoprase.  The  most  common  color,  however,  is 
a  peculiar  tendon-like  tint,  and  as  such  the  mineral  is  of 
very  common  occurrence  in  Arizona.  It  is  a  secondary 
mineral,  resulting  from  the  disintegration  of  rocks, 
usually  volcanic,  by  which  an  excess  of  free  silica  is 
produced.  The  mineral  is  then  deposited  in  the  cracks 
and  other  cavities  of  the  rock,  and  being  much  harder 
than  the  rock  in  which  it  occurs,  endures  long  after  the 
main  portion  of  the  mass  has  suffered  complete  disinte- 
gration. Thus  it  is  frequently  found  as  pebbles  and 
rounded  masses  in  the  streams  and  on  the  mesas. 

Agate. — This  is  simply  a  variegated  chalcedony,  the 
irregularities  sometimes  taking  the  form  of  bands  which, 
when  parallel  and  of  alternate  light  and  dark  colors,  con- 


OXIDES  37 

stitute  the  onyx  and  sardonyx.  When  the  variegations 
are  in  the  form  of  moss-like  or  dendritic  growths,  the 
specimen  is  known  as  the  moss-agate.  The  mineral  is 
formed  in  exactly  the  same  manner  as  chalcedony,  the 
variegated  tints  being  due  to  small  amounts  of  various 
oxides,  which  serve  merely  as  coloring  matter.  Some  of 
the  most  beautiful  agates  are  formed  in  lavas,  which 
when  they  were  erupted,  contained  such  quantities  of 
gas  and  water  vapor,  that  large  rounded  cavities  were 
formed  by  their  expansion  when  the  lava  cooled.  As 
described  above,  these  cavities  become  filled  with  silicious 
matter,  which  from  year  to  year  varied  slightly  in  com- 
position, thus  giving  rise  to  a  concentric  banded  struc- 
ture. Sometimes  the  cavity  is  not  completely  filled,  in 
which  case  the  mineral  is  like  a  hollow  shell,  frequently 
lined  with  the  most  beautiful  crystals.  These  are  called 
geodes,  and  are  occasionally  found  in  the  streams  of 
Arizona,  where  they  have  been  washed  out  of  the  rock 
which  contained  them.  They  are  also  found  in  place 
embedded  in  what  is  known  as  the  Aubrey  limestone, 
which  is  abundant  in  the  northern  part  of  the  State. 
Agates  in  Arizona  have  been  described  from  the  lavas  of 
the  Tucson  range  of  mountains,1  and  as  blue  gray 
amygdules  coated  with  opal  from  other  portions  of  the 
State.2 

Diatomaceous  Earth.  —This  is  a  variety  of  silica,  per- 
haps more  accurately  described  under  opal,  which  forms 
the  shell  of  microscopic  organisms.  It  is  deposited  in 

1  Guild  :  Am.  Jour.  Sc.,  4th  series,  20,  p.  313,  Plate  IX. 

2  Kunz  :  Gems,  p.  130. 


38  THE    MINERALOGY    OF    ARIZONA 

quiet  water,  either  lake  or  ocean.  A  snow  white  deposit 
of  this  material,  occurring  in  the  San  Pedro  Valley,  and 
associated  with  fine  volcanic  ash,  has  been  described  by 
Professor  W.  P.  Blake.1  Deposits  of  the  same  material 
are  also  described  in  the  Bradshaw  folio  of  the  United 
States  Geological  Survey. 

Petrified  Wood. — This  form  of  silica  or  quartz  is  very 
abundant  in  Arizona,  whose  specimens  are  justly  prized 
by  museums  and  private  collectors  in  all  parts  of  the 
world.  The  material  is  especially  abundant  in  the  re- 
gion of  the  Grand  Canon  and  extending  southward  along 
the  Colorado  river  to  Yuma.  The  petrifaction  sometimes 
takes  the  form  of  impure  silicious  matter,  in  which  the 
exact  form  and  structure  of  the  wood  is  preserved,  but 
not  in  very  pleasing  tints.  At  other  times  the  silicifica- 
tion  is  in  the  form  of  chalcedony,  jasper,  agate,  etc.,  giv- 
ing rise  to  very  striking  and  beautiful  specimens.  It  is 
remarkable  that  all  these  brilliant  tints  are  sometimes 
mingled  in  the  same  piece.  A  section  of  a  large  log 
showing  these  variegated  tints,  weighing  over  15  tons, 
has  been  polished  and  deposited  in  the  Museum  of  Nat- 
ural History  in  Paris.  The  most  highly  prized  specimens 
are  found  in  the  vicinity  of  Holbrook  and  Adamana, 
where  many  square  miles  are  literally  covered  with 
petrified  logs,  branches  and  small  broken  fragments  of 
bright  colors.  These  have  been  highly  prized  by  the 
Indians  on  account  of  their  hardness  and  color,  and  may 
be  found  with  other  Indian  relics  in  various  parts  of  the 
southwest. 

i  Am.  In.  Min.  Eng.,  33,  1903,  38. 


Fig.  2. 
A  microscopic  section  of  petrified  wood,  showing  the  original  cell  structure. 


OXIDES  39 

Geologically  the  petrified  wood  of  Arizona  is  supposed 
to  occur  in  the  middle  Triassic  beds  called  by  Powell  the 
Shinarup  group  and  possessing  a  thickness  of  about  1600 
feet.  The  petrified  wood  is  found  throughout  the  entire 
thickness. 

Theory  of  Petrifaction.  —  Petrifaction  takes  place 
through  well  known  processes  of  chemistry,  by  which 
the  molecules  of  a  substance  are  removed  one  by  one  and 
the  molecules  of  another  material  deposited  in  their  places. 
It  may  be  likened  to  a  house  originally  built  of  brick  in 
which  each  brick  is  carefully  removed  one  by  one  and 
a  block  of  marble  put  in  its  place  until  the  entire  house 
is  changed  to  marble,  yet  the  shape  of  the  original  struc- 
ture during  the  whole  process  in  maintained.  Thus  when 
a  forest  becomes  buried  and  subjected  to  the  action  of 
silicious  waters,  usually  hot,  a  particle  of  wood  decays  and 
a  molecule  of  silica  is  moulded  into  its  place,  the  process 
being  carried  on  with  such  delicacy  that  the  cells,  annu- 
lar rings,  bark,  knots  and  other  characteristic  features 
are  accurately  preserved  in  stone.  How  completely  and 
delicately  this  replacement  process  has  progressed  may 
be  seen  by  the  accompanying  cut  which  is  a  reproduction 
of  a  photomicrograph  of  a  thin  section  taken  across  the 
grain.  Replacement  processes  of  this  nature  are  well 
known  in  mineralogy  and  in  fact  are  the  chief  agencies 
at  work  in  producing  ore  deposits  of  sufficient  enrich- 
ment to  be  of  economic  value.  (See  Chalcocite,  p.  25.) 

Jasper. — Jasper  occurs  in  a  variety  of  colors  and  differs 
from  chalcedony  in  being  more  opaque  and  less  pure. 


4O  THE    MINERALOGY    OF    ARIZONA 

The  common  color  is  red,  and  in  this  shade  it  is  frequently 
found  in  pebbles  in  the  streams  and  in  angular  fragments 
on  the  mesas  and  in  the  mountains  of  the  State.  In 
the  Petrified  Forest,  as  described  above,  it  is  abundant 
as  jasperized  wood. 

Chrysophase. — Blue  and  bluish  green  copper-stained 
chalcedony  has  been  found  in  abundance  near  Globe. 
' '  The  mineral  occurs  in  small  stringers  in  the  Keystone 
copper  mine  in  that  district.  The  copper  ore  of  this 
mine  is  said  to  be  principally  chrysocolla  or  silicate  ore. 
The  chalcedony  varies  in  color  from  bright  to  pale  blue, 
bluish  green,  and  nearly  apple-green,  and  is  more  or  less 
translucent.  In  some  places  the  color  occurs  in  curved 
layers  and  varies  in  intensity,  thus  bringing  out  the 
mammillary  structure  of  chalcedony  in  peculiar  wavy 
markings.  In  other  places  the  color  approaches  that  of 
chrysoprase,  or  resembles  that  seen  in  certain  artificially 
colored  chalcedony.  Mr.  Wightman  reports  a  sale  of 
probably  200  pounds  of  selected  material  during  1907  by 
the  miners  at  Globe.  After  cutting,  this  blue  chryso- 
prase brings  locally  from  $3.00  to  $10.00  a  piece  for  the 
best  grades. ' ' l 

Flint  and  Chert. — These  are  still  less  pure  varieties  of 
silica.  They  are  found  as  pebbles  in  the  streams,  as  ir- 
regular nodules  in  limestone,  especially  in  the  Aubrey 
limestone  in  the  Grand  Canon  region,  and  in  various 
other  forms. 

Amethyst,  or  amethystine  quartz  is  clear  quartz  col- 

i  Min.  Res.,  U.  S.  G.  S.,  1907,  p.  802. 


OXIDES  41 

ored  purple  by  traces  of  manganese.  It  is  sometimes 
met  with  in  the  quartz  veins  of  the  State,  but  in 
such  quality  as  to  make  it  desirable  only  as  museum 
specimens.  Mr.  Kunz  has  described  it  as  occurring  in 
cavities  in  the  petrified  wood  of  Arizona.1 

In  the  McConnico  district  it  is  found  in  precambrian 
rocks,  sometimes  in  samples  of  great  beauty.  One  crys- 
tal is  reported  to  have  been  sold  to  Tiffany,  of  New 
York  City,  for  $59. oo.2 

Opal,  Si02,  H20 

Common  opal  is  similar  to  chalcedony  in  composition 
and  appearance,  but  is  uncrystallized  and  contains  a 
varying  amount  of  water.  The  precious  varieties  are 
not  found  in  Arizona.  Semi-opal  and  the  clear  variety, 
hyalite,  are  occasionally  found  associated  with  other 
modifications  of  silica.  Kunz  has  mentioned  hyalite  in 
Yavapai  County. 

Cuprite,  Cu20 

The  red  oxide  of  copper  or  cuprite,  occurs  in  massive 
varieties,  resembling  hematite,  in  crystalline  modifica- 
tions in  the  form  of  cubes,  octahedrons  and  dodecahe- 
drons, and  in  capillary  incrustations  of  vivid  red.  This 
latter  variety  is  sometimes  known  as  plush  copper  ore 
and  chalcotrichite,  and  the  transparent  variety  as  ruby 
copper.  Ruby  copper  forms  beautiful  specimens  when 
first  taken  from  the  mine  but  they  soon  become  dulled 

1  Gems,  p.  116. 

2  U.  S.  G.  S.,  Min.  Res.,  1908. 


42  THE    MINERALOGY    OF    ARIZONA 

on  exposure  to  light.  Plush  copper  which  is  more  brill- 
iant red  is  hardly  effected  by  sunlight.  All  of  the  varie- 
ties mentioned  above  are  frequently  met  with  in  Arizona 
and  are  especially  abundant  in  the  Copper  Queen  mines  at 
Bisbee  and  in  the  Clifton-Morenci  district.  They  are  as- 
sociated with  native  copper,  hematite,  limonite,  chryso- 
colla  and  the  other  secondary  ores  of  copper.  Very 
pleasing  museum  specimens  are  obtained  from  the  Globe 
mines  which  consist  of  massive  dark  brown  cuprite  in 
which  are  little  veinlets  and  irregular  spots  of  delicate 
blue  chrysocolla. 

Tenorite,  CuO 

This  is  a  somewhat  rare  mineral  and  is  known  as  black 
oxide  of  copper.  It  is  found  in  a  pulverulent  condition 
mingled  with  manganese  dioxide  and  associated  with 
other  oxidized  material  in  the  Copper  Queen  mines.  It 
is  thought  to  be  still  forming  in  the  caverns  there  as  the 
mineral  is  frequently  found  covering  the  floor  of  cavities 
where  it  has  dropped  from  above.1 

Ice,  H20 

Except  on  high  mountains  and  in  the  northern  part  of 
the  State  this  mineral  in  the  solid  or  crystallized  con- 
dition is  rare  in  Arizona.  On  the  northern  slopes  of  the 
San  Francisco  mountains  it  is  sometimes  found  even  in 
summer  months  in  the  well-known  form  of  snow.  In  the 
southern  portion,  the  high  mountain  ranges  are  frequent- 
ly covered  with  it  during  the  winter,  and  in  the  valleys 

i  Ransome  :  U.  S.  G.  S.,  PP.  No.  21,  p.  128, 


OXIDES  43 

it  is  well  known  as  frost,  and  as  thin  coverings  on  water 
occasionally  seen  in  the  early  morning. 

Ice  Caves. — In  the  vicinity  of  Flagstaff  there  are 
numerous  small  caves  found  in  both  basaltic  and 
limestone  rocks.  A  few  of  these  have  been  known 
to  contain  ice  throughout  the  year.  It  is  the  cus- 
tom of  picnic  parties  to  visit  these  localities,  well 
supplied  with  cream  and  other  dainties,  which  are 
then  well  frozen  by  the  ice  thus  prepared  and  stored 
by  nature.  The  writer  visited  one  of  these  caves  in 
the  summer  of  1906.  It  was  located  on  the  black  lava 
flow  at  the  base  of  Sunset  Peak  where  the  streams  of  lava 
had  evidently  cooled,  forming  a  solid  crust  of  basalt 
which,  due  to  further  movement  of  the  mass  beneath,  had 
broken  up  the  lava  crust  into  a  heterogeneous  mass  of 
angular  blocks  and  fantastic  shapes  of  such  complexity  as 
to  make  description  impossible.  It  most  resembles  an 
ice-dam  formed  during  the  spring  on  many  of  the  northern 
rivers,  except  that  the  material  is  black  and  covered  by 
numerous  small  craters  caused  by  the  escape  of  steam 
from  beneath.  In  this  irregular  mass  are  numerous  small 
caves  formed  by  the  piling  up  of  blocks  of  basalt  as  well 
as  by  the  recession  of  liquid  lava  leaving  cavities  with  thin 
dome-like  roofs.  In  these  cavities  the  ice  has  collected 
during  the  spring  and  winter  months  and  owing  to  the 
nonconducting  character  of  the  rock,  does  not  completely 
thaw  during  the  warm  summer.  It  had  been  preserved 
by  nature  very  much  as  ice  is  stored  in  northern  climates, 
by  packing  in  some  nonconducting  substance.  In  these 


44  THE  MINERALOGY  OF  ARIZONA 

caves  the  ice  appears  as  coverings  on  the  floors  and  as 
stalactites  (icicles)  hanging  from  the  ceilings. 

Hematite,  Fe203 

This  well  known  mineral,  the  anhydrous  oxide  of  iron, 
is  found  everywhere  and  in  a  great  variety  of  forms.  It 
is  abundant  in  all  mines  where  oxidation  of  sulphides  has 
taken  place  and  is  the  cause  of  the  red  color  of  many  ores, 
minerals  and  soils.  When  well  crystallized  it  is  called 
specular  iron  and  frequently  forms  beautiful  cabinet 
specimens  especially  when  showing  an  iridescent  tarnish. 
It  is  frequently  found  in  Arizona  as  a  contact  mineral 
associated  with  epidote  and  similar  minerals.  It  is  fur- 
ther found  in  large  beds  where  it  can  be  utilized  as  a  basic 
flux  in  smelting. 

Magnetite,  Fe304 

This  is  the  black  magnetic  oxide  of  iron,  and  is 
found  as  a  microscopic  accessory  in  nearly  all  rocks. 
From  this  source  it  finds  its  way  into  black  sands  and 
similar  deposits.  It  is  further  found,  like  hematite, 
associated  with  contact  minerals  and  in  a  great  variety 
of  ways.  In  the  Tucson  mountains  it  is  found  as  rounded 
transported  blocks,  frequently  pitted  in  a  manner  to  re- 
semble meteorites. 

Pyrolusite,  Mn02 

The  Black  oxide  of  manganese,  or  pyrolusite,  has  been 
noted  in  the  Clifton-Morenci  district  mixed  with  limonite.1 
Samples  from  other  localities  have  been  received  at  the 

i  I^indgren  :  U.  S.  G.  S.,  PP.  No.  43. 


OXIDES  45 

University  of  Arizona,  but  data  regarding  their  mode  of 
occurrence  are  lacking. 

Limonite,  Fe2033H20 

Limonite,  or  the  hydrous  oxide  of  iron  is  very  abun- 
dant ;  it  is  associated  with  oxidized  ores  in  the  Copper 
Queen  mine  where,  together  with  hematite,  it  is  the  cause 
of  the  reddish  color  of  the  ores.  It  is  frequently  found 
in  mammillary  and  kidney  shapes.  In  general  its  mode 
of  occurrence  is  similar  to  that  of  hematite,  from  which 
it  can  hardly  be  distinguished  except  by  chemical  means. 


VI.  OXYGEN  SALTS 


(i).  CARBONATES 

Calcite,  CaC03 

The  various  modifications  of  calcite  are  found  in  nearly 
every  mountain  range  of  the  State  and  have  frequently 
been  described  in  geological  literature. 

Limestone. — This  well  known  rock  or  mineral  varies 
greatly  in  composition  and  appearance  in  different  parts  of 
the  State.  In  many  places  especially  in  the  vicinity  of 
the  Grand  Canon,  it  is  very  impure  containing  often  large 
quantities  of  both  silica  and  magnesia.  The  silica  is 
sometimes  in  the  form  of  nodules  and  geodes  and  some- 
times as  fine  sand  or  silt  intimately  mixed  with  the  car- 
bonate. The  magnesium  is  always  in  the  form  of  mag- 
nesium carbonate.  The  following  analyses  made  by  the 
writer  on  samples  obtained  in  the  vicinity  of  Flagstaff 
will  give  an  idea  of  its  composition.  In  geological  litera- 
ture the  formation  is  known  as  the  Aubrey  Limestone. 

No  i  No  2  No  3 

Per  cent.        Per  cent.         Per  cent. 

Silica •   34.10  17.00  72.21 

Iron  and  alumina 1.60  i.oo  2.91 

Calcium  carbonate 33. 8 r  48.20  18.60 

Magnesium  carbonate...  26.43  34-4°  5-62 

Total 95-94         100.60  99-34 

It  will  be  seen  from  the  analyses  that  No.  3  at  least  is 
a  calcareous  sandstone  rather  than  limestone,  and  in  fact, 


OXYGEN    SAWS  47 

all  gradation  may  be  found  in  this  district  between  pure 
sandstone  on  the  one  side  and  pure  limestone  on  the  other. 
The  formation  known  as  the  Red  Walled  Limestone  in 
the  Grand  Canon  is  much  purer  in  composition.  A  large 
area  of  this  has  been  exposed  in  the  vicinity  of  Flagstaff 
through  the  intrusive  action  of  some  of  the  crystalline 
lavas  of  the  San  Francisco  mountain  district.  It  is  found 
in  direct  contact  with  andesite  on  the  north  flank  of 
Elden  Peak,  about  nine  miles  from  town.  It  has  been 
used  in  the  manufacture  of  lime,  and  is  said  to  give  ex- 
cellent results.  Its  chemical  composition  is  represented 
in  the  table  below. 

Silica * . . .  0.27 

Iron  and  alumina 1.24 

Calcium  carbonate 95.84 

Magnesium  carbonate 0.90 

Alkalies 0.48 


Total 98.73 

An  interesting  case  of  contact  metamorphism  was  ob- 
served at  the  immediate  contact  of  this  pure  limestone  or 
marble  with  the  crystalline  andesite.  Here  the  lime- 
stone has  become  very  fine  grained  and  taken  on  the  ap- 
pearance of  lithographic  stone.  The  alteration  is  plainly 
due  to  the  influence  of  the  igneous  mass  by  which  the 
marble  or  limestone  has  become  both  silicified  and  dolo- 
mitized.  The  chemical  reactions  which  have  taken  place 
in  this  transformation  may  be  inferred  from  the  following 
table,  which  contains  the  analysis  of  a  sample  taken  about 
five  feet  from  the  contact. 


48  THE    MINERALOGY    OF    ARIZONA 

Per  cent. 

Silica 19.41 

Iron  oxide 2.02 

Alumina   8.82 

Calcium  carbonate 46.30 

Magnesium  carbonate 25.43 


Total 101.98 

Marble. — Marble  or  crystallized  limestone  has  fre- 
quently been  used  in  Arizona  for  building  purposes.  The 
local  demand,  however,  is  very  slight,  and  freight  rates 
are  such  that  it  cannot  be  transported  great  distances. 
Samples  sent  to  the  University  of  Arizona,  from  various 
localities,  seem  to  show  that  it  is  abundant  and  frequently 
of  very  pleasing  color. 

Onyx  Marble. — This  beautiful  stone,  more  frequently 
known  as  Mexican  Onyx,  has  been  found  in  Arizona  in 
tints  and  variegated  effects  equal  in  every  respect  to  the 
Mexican  product.  Mineralogically  it  may  be  considered 
as  stratified  and  variegated  calcite  or  aragonite,  the  bands 
and  irregular  coloring  effects  being  caused  by  the  arrange- 
ment of  such  foreign  pigments  as  iron  oxide  in  various 
stages  of  oxidation  and  hydration.  The  most  important 
locality  in  Arizona  is  near  Mayers  about  26  miles  from 
Prescott.  The  deposit  is  approximately  twenty  acres  in 
extent  and  the  workable  material  is  described  as  occur- 
ring in  bowlders  containing  from  two  to  thirty  cubic  feet.1 
Other  localities  are  Greaterville,  Kirkland  Valley,  and 
Oak  Creek. 

Caliche. — This  is  a  word  of  Spanish  origin  loosely  em- 

i  W.  P.  Blake  :  Rep.  to  Gov.,  1899. 


OXYGEN   SAI/TS  49 

ployed  by  the  Mexicans  and  others  in  the  south-western 
United  States  and  Mexico  to  designate  almost  any  non- 
crystalline  crust.  It  was  perhaps  first  used  by  the  Chil- 
lians  who  applied  it  to  the  soluble  saline  crusts  of  their 
country  which  consisted  mostly  of  crude  nitre  and  other 
soluble  constituents.  In  some  parts  of  California  the  term 
is  still  used  in  a  similar  manner,  perhaps  with  particular 
reference  to  the  top  coatings.1  In  Arizona  the  term  is 
usually  applied  to  a  calcareous  deposit  of  varying  hard- 
ness found  to  exist  in  many  soils  and  gravels.  It  results 
from  the  evaporation  of  meteoric  water  in  situ,  and  of 
water  brought  down  from  the  mountains  and  distributed 
throughout  the  valley  in  the  form  of  underground  streams 
and  reservoirs.  The  calcareous  matter  owes  its  ultimate 
origin  to  the  decomposition,  through  the  influence  of 
dilute  solutions  of  carbonic  acid,  of  complex  calcium  sili- 
cates of  the  soil  and  rocks.  The  following  reaction  is 
given  as  an  illustration  of  this  decomposition : 

Lime  Feldspar  +  Alkali  Feldspar  -f-  Carbonic  Acid  = 
CaAl2Si208  KAlSi308  H2CO3 

Calcite  (caliche)  -f-  Muscovite  (sericite)  -f  Quartz. 
CaC03  H2KAl3Si3012  2SiO2 

The  reaction  f  urthur  explains  the  presence  of  alkali  in 
the  soil,  since  the  continued  action  of  CO2,  or  H2CO3, 
would  convert  the  muscovite  into  K2CO3  and  kaolin. 
The  two  constituents  kaolin  and  alkali  may  also  be 
formed  direct  from  the  feldspar  as  shown  by  the  follow- 
ing reaction  : 

1  Bailey  :  The  Saline  Deposits  of  Cal.,  Bui.  No.  24,  Cal.  State  Min.  Bureau. 


50  TH£    MINERALOGY    OF    ARIZONA 

Ortlioclase     +     Water     -f-     Carbon  Dioxide    — 
6KAlSi308  6H20 


Kaolin     -f     Alkali     -f     Silica. 
3H4A.l2Sis09  3K2C03  i2SiO2. 

The  alkali  is  not  found  to  any  extent  in  the  caliche,  since 
its  great  solubility  compels  it  to  remain  mostly  in  the  un- 
derground waters.  The  kaolin,  or  clay,  and  the  silica  rep- 
resented in  the  above  reaction  are  always  present  in  large 
quantities.  The  muscovite  then  is  only  an  intermediate 
product,  easily  seen  in  decomposing  rocks  by  means  of  the 
microscope,  but  later  altering  into  kaolin  or  clay.  As  may 
easily  be  inferred,  caliche  is  a  deposit  occurring  only  in 
arid  countries  where  evaporation  is  rapid  and  circulation 
of  at  least  surface  waters  slow  and  incomplete.  It  is 
therefore  abundant  in  Arizona  and  in  arid  portions  of 
California  and  Mexico.  In  appearance  it  is  a  light  buff 
shading  to  white,  and  seems  to  be  made  up  of  the  ordi- 
nary constituents  of  the  soil  such  as  silt,  sand,  gravel  and 
small  pebbles  firmly  cemented  together  by  calcium  car- 
bonate. Occasionally  it  is  faintly  stratified,  the  layers 
being  due  to  successive  depositions  from  solution  rather 
than  sedimentation.  As  a  deposit  in  ordinary  soils  it  is 
always  formed  beneath  the  surface  ;  where  erosion  has 
not  taken  place,  there  are  a  few  inches  to  several  feet  of 
earth  on  top.  Its  occurrence,  however,  is  not  limited  to 
within  a  few  feet  of  the  surface  ;  it  is  sometimes  found  in 
layers  of  varying  thickness  alternating  with  loose  sand  or 
gravel  to  a  depth  of  seventy-five  feet  or  more.  The  deeper 
layers  differ  somewhat  in  character  from  those  near  the  sur- 
face. These  usually  consist  of  coarser  particles  of  gravel 


OXYGEN   SALTS  51 

and  pebbles  and  of  even  small  bowlders  cemented  by  a 
more  crystalline  calcium  carbonate  into  a  mass  of  such  hard- 
ness that  a  well  can  be  sunk  into  it  only  with  the  greatest 
difficulty.  Indeed,  it  is  sometimes  necessary  to  resort  to 
the  use  of  blasting  powder.  The  spaces  between  the 
pebbles  are  lined  with  drusy  scalenohedral  crystals  of 
calcite  and  even  well  formed  geodic  cavities  are  some- 
times observed.  Evidently  the  deposition  here  took  place 
under  more  uniform  and  deeper  seated  conditions  than 
those  which  gave  rise  to  the  finer  grained  amorphous 
surface  deposits.  The  deposit  is  not  merely  local  in 
character,  but  many  hundreds  of  square  miles  are  ren- 
dered useless  for  agricultural  purposes  by  its  presence. 

As  previously  stated,  it  would  seem  that  the  two  modi- 
fications of  this  deposit  described  above  owe  their  origin 
to  two  closely  related  phenomena  :  (i),  the  layers  near 
the  surface,  to  the  evaporation  of  meteoric  waters  in  situ  ; 
(2),  the  deep-seated  layers,  to  evaporation  of  waters 
brought  up  by  capillary  attraction  to-some  definite  position 
which  depends  upon  local  conditions,  such  as  fineness  of 
material,  pressure,  etc.  Of  course  it  can  easily  be  seen  that 
where  underground  waters  exist  near  the  surface  the 
top  layers  might  be  formed  in  the  way  last  mentioned. 
Then  evaporation  at  depth  would  not  take  place.  Again, 
in  places  where  there  is  no  underground  water  at  reason- 
able depths,  only  the  first  mentioned  cause  would  be  oper- 
ative. In  either  case  the  deposition  takes  place  beneath 
the  surface  and  never  precisely  upon  it.  The  reason  for 
this  is  to  be  found  in  the  climatic  conditions  of  the  South- 
west. Immediately  after  a  rain  the  sun  quickly  reap- 


52  THE    MINERALOGY    OF    ARIZONA 

pears,  rapidly  drying  the  surface  of  the  ground  and  thus 
preventing  furthur  action  of  capillary  attraction.  Iftie 
earth  becoming  like  a  dry  sponge  is  unable  to  soak  up 
moisture  from  below.  The  depth  to  which  this  superficial 
drying  takes  place  depends  upon  local  conditions  such  as 
texture  of  the  soil,  vegetation  and  other  features.  The 
remaining  meteoric  water  is  now  brought  up  by  capillary 
attraction  to  the  point  where  evaporation  begins  and 
capillary  attraction  ends.  This  action  continues  until  all 
of  the  water  is  evaporated,  is  repeated  after  the  next 
rain,  thus  giving  rise  to  faint  stratifications,  until  finally 
a  deposit  of  considerable  thickness  is  formed. 

The  deposition  taking  place  through  the  evaporation  of 
underground  waters  may  progress  at  any  depth,  though 
with  less  rapidity  as  the  depth  increases.  The  exact 
position  in  which  the  deposit  is  forming  during  any 
series  of  years  depends,  first,  upon  the  height  of  the 
underground  water,  and  second,  upon  the  distance 
through  which  capillary  attraction  is  able  to  act  under 
the  existing  conditions  of  porosity,  pressure,  or  other  de- 
termining agents.  Thus,  if  the  underground  water  at  a 
certain  time  is  found  at  a  depth  of  say  eighty-five  feet, 
the  calcareous  deposit  may  actually  form  at  that  time  at 
a  depth  of  seventy-five  feet  or  more.  Cavities  are 
actually  found  at  this  depth  incompletely  filled  with  mi- 
nute crystals,  a  fact  which  suggests  that  the  deposition  is 
still  going  on. 

The  explanation  of  the  alternate  layers  of  calcareous 
material  is  to  be  sought  in  the  possibility  of  the  under- 
ground waters  having  occupied  higher  levels  in  former 


OXYGEN   SALTS  53 

periods  of  time.  The  Tucson  Valley,  for  example,  is 
filled  with  debris  contributed  by  the  high  surrounding 
mountains.  All  of  this  material  was  at  one  time  on  the 
slopes  and  mountain  tops  of  these  ranges.  Their  alti- 
tude, then,  must  have  been  a  few  thousand  feet  higher 
than  the  present  time.  As  is  well  known  this  would 
have  had  the  effect  of  greatly  increasing  the  annual  pre- 
cipitation which  in  due  course  would  have  greatly  aug- 
mented the  quantity  of  underground  water.  Regarding 
the  outlet  of  the  underground  water  there  is  at  present 
but  little  known,  but  it  is  very  probable  that  erosion  and 
the  solvent  action  of  water  has  had  the  effect  of  decreas- 
ing its  elevation.  Thus  it  seems  quite  evident  from  well 
established  facts  of  geology  that  the  underground  water 
of  this  valley,  occupied  in  former  periods  of  time  con- 
siderable higher  levels.  Evaporations  at  points  slightly 
above  these  surfaces,  as  described  above,  would  ac- 
count for  the  repetition  of  the  caliche  beds. 

Caliche,  as  the  term  is  used  in  Arizona,  was  first  fully 
described  in  scientific  literature  by  Professor  W.  P. 
Blake,1  who  explained  its  origin  as  entirely  through 
evaporation  of  underground  waters  brought  up  from  be- 
low by  capillary  attraction.  Dissenting  from  this  view, 
Professor  R.  H.  Forbes  holds  that  all  of  these  deposits, 
even  the  deep-seated  ones  are  formed  by  the  evaporation 
of  rain  water  which  has  percolated  to  a  depth  of  three  or 
four  feet,  decomposing  the  constituents  of  the  soil 
through  the  action  of  carbon  dioxide.  The  calcareous 

i  The  Caliche  of  Southern  Arizona:  Trans.  Am.  In.  Min.  Eng.,  31,  1901, 
p.  220. 


54  THE    MINERALOGY    OF    ARIZONA 

material  thus  formed  is  left  behind  in  the  soil  on  evapor- 
ation of  the  water,  a  process  which  is  repeated  until  a 
limy  hardpan  is  formed.  "The  different  layers  formed 
at  different  depths  below  the  surface  mark  the  various 
levels  which  for  geological  reasons  remained  constant  for 
a  long  enough  period  of  time  to  permit  the  formation  of 
a  layer  of  caliche  just  below  the  surface  of  that  time."1 

Professor  C.  F.  Tolman  would  confine  the  term  caliche 
to  the  amorphous  surface  crusts  and  not  the  crystalline 
cements  of  the  desert  gravels.  "This  cement,"  he  states, 
* '  is  primarily  due  to  the  fact  that  these  basins  are  practi- 
cally undrained.  The  deeper  cement,  moreover,  may  be 
largely  recrystallized  crusts,  and  without  direct  relation 
to  any  change  in  climate  or  water  level."2  Professor 
Tolman  also  calls  attention  to  the  probability  of  the 
Paleozoic  limestones  being  an  original  source  of  much  of 
the  calcareous  material.3 

Siderite,  FeC03 

This  mineral,  sometimes  known  as  spathic  iron,  is  fre- 
quently developed  in  Arizona  as  an  alteration  product 
near  limestone  especially  where  sulphides  of  iron  are  ox- 
idizing. In  the  Tucson  mountains  it  has  been  observed 
as  a  decomposition  product  of  the  ferromagnesian  constit- 
uents of  basic  lavas,  in  which  it  is  deposited  in  amygda- 
loidal  cavities  and  cracks  together  with  chalcedony,  cal- 
cite  and  agate. 

1  Quoted  in  Underground  Waters  of  Salt  River  Valley,  U.  S.  G.  S.,  W.  S.  P., 
No.  136,  p.  no. 

2  Manuscript. 

*  Pub.  113,  Carnegie  Inst.  of  Wash.,  73. 


OXYGEN   SALTS  55 

Rhodochrosite,  MnC03 

So  far  as  the  writer  knows,  this  mineral  in  a  pure  con- 
dition has  not  been  reported  from  Arizona.  A  manganif- 
erous  limestone,  however,  is  found  in  the  Tombstone 
district  and  on  decomposition  yields  manganese  oxide 
containing  silver.1 

Cerussite,  PbC03 

The  carbonate  of  lead,  a  heavy  and  when  pure  a  white 
or  transparent  mineral,  is  frequently  met  with  in  the  lead 
and  silver  mines  of  the  State  as  an  alteration  product  of 
galena.  The  galena  first  oxidizes  to  the  sulphate  or  angle- 
site,  and  then  coming  in  contact  with  solutions  containing 
carbonates  a  substitution  takes  place  by  which  the  sul- 
phate radical  is  removed  and  the  carbonate  radical  in- 
stalled. A  crystallographic  study  has  been  made  by 
Pirsson  on  samples  from  the  Red  Cloud  mine.2  In  the 
Bisbee  district  it  is  found  in  Hendricks  Gulch  associated 
with  limestone.  Here  it  occurs  as  an  impure  friable  mass 
which  in  mining  breaks  up  into  fine  sand.  Hence  this 
variety  is  sometimes  known  as  cerussite  sand. 
Azurite,  2CuC03.Cu(OH)2,and  Malachite,  CuC03.Cu(OH)2 

The  blue  and  green  carbonate  are  abundant  in  Arizona 
and  have  been  so  frequently  mentioned  in  the  description 
of  mining  districts  that  little  space  will  be  devoted  to  them 
here.  The  two  minerals  are  nearly  always  associated 
with  each  other  even  in  the  same  hand  specimen,  some- 
times so  intricately  mingled  in  delicate  wavy  forms  as  to 
yield  very  striking  and  beautiful  effects  when  polished. 

1  W.  P.  Blake  :  Rep.  to  Gov.,  1899. 

2  Am.  Jour.  Sc.,  42,  p.  405. 


56  THE    MINERALOGY    OF    ARIZONA 

The  crystalline  varieties  of  azurite  sometimes  develops  in 
aggregates  of  rounded  bunches,  arranged  in  such  a  man- 
ner as  closely  to  resemble  clusters  of  grapes.  The  green 
carbonate  more  often  appears  as  silky  radiating  tufts  or 
incrustations  on  botryoidal  surfaces,  giving  the  appear- 
ance of  green  plush.  These  beautiful  forms  are  found 
as  the  lining  of  caves  or  small  cavities.  Here  also  are 
frequently  developed  stalactites  containing  both  minerals 
in  concentric  layers.  Cross  sections  of  these  when  pol- 
ished show  concentric  wavy  rings  of  blue  and  green  car- 
bonates. Dr.  G.  F.  Kunz  has  applied  the  name  azur- 
malachite  to  such  samples  when  employed  as  a  gem. 

These  two  minerals  are  always  secondary  and  are  never 
found  at  great  depths.  They  result  from  the  oxidation 
of  the  various  sulphides  of  copper  by  which  action  the 
soluble  sulphates  are  formed,  which  on  coming  in  contact 
with  limestone  or  carbonated  waters,  react  to  form  the 
carbonates.  These  are  then  deposited  from  solution  in 
the  delicate  forms  described  above. 

Aurichalcite,  2(Zn,  Cu)C03.3(Zn,  Cu)(OH)2 

This  rare  mineral  occurs  in  pale  green  and  bluish 
flakes.  It  has  been  reported  from  the  Copper  Queen 
mine  at  Bisbee  and  from  theCatalina  mountains.  (Dana). 


(2).  SILICATES 

The  Feldspars 

Orthoclase,  KAlSi308. — This  is  a  rock-forming  mineral, 
and  as  a  constituent  of  granite  and  the  corresponding 


OXYGEN   SALTS  57 

acid  eruptives,  such  as  rhyolites,  felsites,  and  quartz 
porphyries,  is  found  almost  everywhere  in  the  State. 
In  this  mode  of  occurrence  it  develops  in  crystals  varying 
from  microscopic  size  to  crystals  an  inch  in  length.  In 
pegmatites,  or  the  light  colored  veins  which  are  nearly 
always  found  crossing  granites  and  similar  rocks,  it  is 
found  associated  with  quartz  and  sometimes  developed  in 
large  masses  of  pure  material.  In  the  pegmatites  of 
southern  California  masses  of  this  kind  are  frequently 
found  weighing  more  than  75  pounds  and  possessing 
uniform  cleavage  and  structure.  Good  crystals  are  fre- 
quently found  ten  inches  in  length.  In  Arizona  there 
are  no  unusual  deposits  of  this  mineral.  A  few  good 
crystals  have  been  found  in  the  pegmatites  of  the  Catalina 
mountains,  near  Tucson,  and  good  white  masses  may  be 
observed  in  many  other  localities.  The  Rincon  mountains 
have  yielded  rather  fine  samples  of  typical  pegmatite. 

Microcline. — This  mineral,  which  has  the  same  chemi- 
cal composition  as  orthoclase,  with  slightly  different 
crystalline  structure,  has  been  observed  as  a  microscopic 
constituent  in  the  tourmaline  aplites  found  in  the  vicinity 
of  Oracle,  in  the  Catalina  mountains. 

Plagioclases — The  plagioclase  feldspars  differ  from 
orthoclase  in  composition  and  crystallization.  Chemically 
they  are  isomorphous  mixtures  of  albite,  NaAlSi3O8,  and 
anorthite,  CaAl2Si2O8,  different  proportions  of  these  two 
molecules  giving  rise  to  the  rather  arbitrary  varieties, 
oligoclase,  andesine,  loboradorite  and  bytownite.  They 
are  all  rock-forming  minerals  and  are  found  in  diorites, 


58  TH£    MINERALOGY    OF    ARIZONA 

gabbros,  and  their  eruptive  equivalents,  andesites  and 
basalts.  Andesites  are  probably  the  most  common  erup- 
tive in  the  Territory,  and  as  constituents  of  these  the 
plagioclases  or  triclinic  feldspars  are  very  abundant. 

Pyroxene 

Pyroxene,  the  common  variety  of  which  is  augite,  is  a 
complex  silicate  of  calcium,  magnesium,  iron,  etc.  It  is 
a  rock-forming  mineral,  and  is  abundant  in  Arizona  as  a 
constituent  of  andesites,  basalts  and  other  rocks. 

Amphibole 

This  mineral  is  similar  to  pyroxene  in  its  chemical 
composition  and  variations.  L,ike  pyroxene,  it  is  very 
abundant  everywhere  as  a  rock-forming  constituent  of 
granites,  andesites,  dike  rocks  and  metamorphic  schists. 
It  is  a  constituent  of  the  more  acid  and  intermediate  rocks, 
while  pyroxene  usually  indicates  a  more  basic  magma. 
Actinolite  and  tremolite  are  the  light  colored  varieties, 
and  are  frequently  found  as  constituents  of  the  crystal- 
line schists.  A  manganiferous  variety,  exact  locality  un- 
known, has  been  analyzed  by  Mr.  Fred.  Hawley,  a 
student  at  the  University  of  Arizona,  with  the  following 
results  : 

Per  cent. 

Silica 49-30 

Ferrous  oxide 15.14 

Alumina 3.10 

Manganese  oxide 6.39 

Calcium  oxide 23.61 

Magnesia o.  14 

Undetermined 2.32 


Total loo.oo 


OXYGEN  SAI/TS  59 

The  mineral  is  dark  brown  with  columnar  divergent 
structure.  The  above  analysis  would  place  the  mineral 
as  near  dannemorite. 

Garnet 

Garnet  is  a  complex  silicate  of  calcium  and  aluminium 
in  which  calcium  is  frequently  replaced  by  more  or  less 
iron  and  magnesium,  and  the  aluminium  by  chromium 
and  iron.  It  varies  in  color  from  white  to  black,  red, 
yellow,  green  and  brown  shades  being  the  most  common. 

Garnetiferous  Sand. — Garnet  is  a  frequent  accessory  in 
schistose  and  granitic  rocks.  These  are  yielded  up  by  the 
rock  on  disintegration  and  owing  to  their  ability  to  resist 
erosion  and  corrosion  collect  in  the  eddies  of  the  stream 
together  with  black  sand  or  magnetite.  Samples  illus- 
trating this  mode  of  occurrence  have  been  collected  from 
the  streams  of  the  Catalina  mountains  which  on  analysis 
are  found  to  correspond  to  the  manganiferous  variety  or 
spessartite. 

Precious  Garnet. — In  the  exteme  northern  part  of  the 
State  the  Moki  Indians  and  others  bring  into  the 
towns  large  quantities  of  loose  garnets  many  of  which  are 
cut  and  show  a  beautiful  dark  ruby  tint.  They  are 
known  among  gem  dealers  as  the  Arizona  rubies  and  are 
without  doubt  the  finest  garnets  in  the  United  States. 
They  are  picked  up  in  gravel  deposits  and  around 
ant-hills  where  these  industrious  workers  have  brought 
them  from  the  surrounding  country.  The  associated 
minerals  are  peridot,  pyroxene,  magnetite  and  similar 
minerals.  The  gem  has  never  been  found  in  place  but 


60  THE)    MINERALOGY    OF    ARIZONA 

owing  to  its  associations,  one  is  authorized  in  assuming 
that  it  was  developed  in  some  of  the  ultra-basic  rocks  such 
as  the  peridotites.  They  are  always  found  in  well  round- 
ed and  polished  pebbles  varying  from  a  few  millimeters  to 
two  centimeters  in  diameter.  The  latter,  however,  are 
never  of  gem  quality.  The  average  size  for  cutting  is 
about  one  carat ;  two  carat  stones  are  abundant  but  the 
three  carat  size  is  very  scarce.  The  smooth  polished  sur- 
faces of  these  fragments  seems  to  be  due  to  wind  erosion 
rather  than  stream.  (See  Mineral  Resources,  1908.)  The 
index  of  refraction  of  these  gems  as  determined  with 
sodium  light  on  a  Fuess  instrument  is  1.7500.  This 
corresponds  to  the  variety  pyrope. 

Yellow  garnet,  or  variety  containing  larger  quantities 
of  lime,  has  frequently  been  received  at  the  University  of 
Arizona  for  identification,  and  a  fine  large  crystal  from 
Gila  Canon  has  been  described  by  Mr.  Kunz.1  The  min- 
eralogical  name  for  this  variety  is  Grossularite. 

Massive  Garnet. — This  variety  of  garnet  is  very  com- 
mon in  many  of  the  mining  districts  of  the  State  hav- 
ing been  developed  by  contact  action  between  limestone 
and  igneous  intrusion.  This  modification  varies  in  color 
from  nearly  black  to  light  yellow  according  to  the  acidity 
of  the  magma.  Near  the  contact  with  basic  eruptives 
the  dark  colored  varieties  are  formed.  It  is  found  in  the 
Clifton-Morenci  district  in  altered  limestone  in  the  form 
of  andradite,  or  common  iron  garnet,  yellow  to  dark 
brown  in  color  and  of  a  resinous  luster.  It  is  further 
found  in  the  same  locality  intergrown  with  magnetite, 

1  Gems,  p.  79. 


OXYGEN   SAVTS  6l 

pyrite,  zinc  blende  and  chalcopyrite.1     It  is  is  also  abun- 
dantly developed  in  the  Silver   Bell,  the   San   Xavier, 
Washington  Camp  and  other  contact  districts. 
Chrysolite,  (Mg,  Fe)2SiO, 

This  is  usually  a  yellowish  green  mineral  consisting  of 
an  isomorphous  mixture  of  the  two  constituents,  iron  and 
magnesium  silicate.  It  is  usually  a  rock-forming  mineral, 
and  as  such  is  more  frequently  known  as  olivine.  It  is  a 
normal  constituent  of  basalts  and  most  gabbros,  and  in 
these  varieties  of  rock  is  of  very  common  occurrence  in 
Arizona.  The  crystals  are  usually  so  small  as  to  escape 
ordinary  observation.  Yet  in  some  of  the  basalts  of  the 
San  Francisco  mountains  crystals  are  found  more  than 
one-half  inch  in  length. 

Peridot. — Crystals  of  sufficient  purity  and  transparency 
to  be  useful  as  a  gem  are  known  as  peridot.  It  is  found 
in  beautiful  tints  near  Talkai,  and  is  frequently  collected, 
together  with  the  red  garnets  with  which  they  are  some- 
times found,  by  the  Indians  and  prospectors.  A  crystal 
from  this  locality,  exhibited  at  the  World's  Fair,  at  Port- 
land, in  1905,  after  being  cut,  was  a  beautiful  gem  of  25% 
carats.  It  was  pale  yellowish  green  and  took  a  brilliant 
polish.  The  gem  variety  of  chrysolite  is  most  often 
found  in  the  streams  as  worn  pebbles,  but  is  occasionally 
found  lining  cavities  in  basaltic  lavas  of  sufficient  clear- 
ness to  be  used  as  a  gem.  Like  garnets,  they  are  found 
around  ant-hills.  One  hill  investigated  by  members  of 
the  United  States  Geological  Survey  was  found  to  be 
made  up  of  75  per  cent,  of  peridot  grains,  the  remainder 

ITJ.  s.  G.  s.,  PP.  NO.  43. 


62  THE    MINERALOGY    OF    ARIZONA 

being  garnet,  quartz,  diopside,  etc.  They  are  brought 
to  the  hills  from  the  surface  over  an  area  of  many  square 
feet  surrounding  the  ant  houses. 

Wollastonite,  CaSiO, 

This  is  a  contact  mineral  sometimes  developed  where 
igneous  rocks  of  intrusion  come  in  contact  with  lime- 
stone. When  pure  it  is  a  white  mineral  of  pearly  luster 
and  breaking  into  splintery  forms.  Contact  deposits  are 
of  common  occurrence  in  Arizona,  but  this  mineral  has 
not  been  described  from  many  localities.  It  has  been 
mentioned  among  the  contact  minerals  in  the  Clifton- 
Morenci  district.1 

Willemite,  Zn2SiO, 

This  anhydrous  silicate  of  zinc  is  usually  a  light  yellow 
mineral  somewhat  resembling  yellow  garnet.  It  has 
been  observed  in  Arizona  only  in  very  small  quantities 
in  the  Clifton-Morenci  district,  on  the  north  side  of 
Modoc  mountain.  It  was  first  discovered  here  by  Mr. 
Boutwell,  and  identified  by  Messrs.  Pirsson  and  Penfield, 
of  Yale.  It  is  described  as  occurring  in  stout  hexagonal 
crystals  with  the  usual  characteristics  of  the  mineral.2 

Dioptase,  H2CuSi04 

This  rare,  gem -like  silicate  of  copper  is  found  in  the 
Clifton-Morenci  district,  as  noted  by  Hill.3  The  crystals 
occur  in  beautiful  emerald  green  incrustations  lining 
cavities  and  associated  with  ferruginous  matter  and 

1  U.  S.  G.  S.,  PP.  No.  43,  p.  124. 

2  U.  S.  G.  S.,  PP.  No.  43. 

3  Am.  Jour.  ScL,  3d  series,  33,  p.  325. 


OXYGEN   SALTS  63 

chrysocolla.     It   has   been   further  reported   from  near 
Riverside,  by  W.  B.  Smith.1 

Vesuvianite 

This  is  a  complex  silicate  containing  calcium,  alumin- 
ium and  a  small  amount  of  fluorine.  It  is  frequently 
developed  in  contact  metamorphism  together  with  garnet 
and  epidote.  In  appearance  it  resembles  the  latter  min- 
eral closely,  but  may  be  distinguished  from  it  easily  by 
the  absence  of  iron  ;  epidote  becomes  magnetic  on  heat- 
ing before  the  blowpipe,  while  vesuvianite  does  not. 
Samples  have  been  received  at  the  University  from  the 
vicinity  of  Jerome,  but  data  regarding  the  mode  of  oc- 
currence are  lacking.  It  doubtless  occurs  in  other 
localities  in  the  State,  but  has  not  been  described  or 
else  has  been  mistaken  for  other  minerals  which  it  re- 
sembles. 

Zircon,  ZrSi04 

This  mineral  has  been  noted  in  Arizona  in  the  Clifton- 
Morenci  district  only  as  a  microscopic  accessory  in  granite 
and  porphyry.2 

Topaz,  (AlF)2Si04 

Samples  of  this  mineral  have  been  received  at  the  Uni- 
versity from  localities  in  the  northern  part  of  the  State 
in  the  form  of  white  broken  fragments,  much  re- 
sembling quartz,  for  which  it  has  frequently  been 
mistaken.  It  can  be  easily  distinguished  from  that  min- 

1  Proc.  Colo.  Sci.  Soc.,  a,  p.  159. 

2  Undgren  :  U.  S.  G.  S.,  PP.  No.  43,  p.  102. 


64  THE    MINERALOGY    OF    ARIZONA 

eral,  however,  by  its  superior  hardness  and  its  cleavage. 
The  exact  locality  of  these  samples  is  not  known. 

Andalusite,  Al2Si05 

The  silicate  of  aluminium  known  as  andalusite  is  devel- 
oped in  slates  and  other  sedimentary  deposits  through 
the  influence  of  both  regional  and  contact  metamorphism. 
In  rare  instances  it  has  been  observed  as  a  pyrogenic  con- 
stituent of  igneous  rocks.  Thus  in  Arizona  it  has  been 
observed  as  a  microscopic  accessory  in  the  granites  in  the 
Globe  copper  district.  It  has  been  suggested  that  possi- 
bly the  mineral  has  been  developed  here  through  recrys- 
tallization  brought  about  by  metamorphic  action,  and  is 
not  an  original  constituent  as  it  would  seem.1 

Cyanite,  Al2Si05 

This  is  a  pale  blue  bladed  mineral  of  the  same  composi- 
tion as  andalusite,  and  though  appearing  quite  different 
from  it,  occurring  in  a  similar  manner.  In  a  ground  mass 
consisting  of  quartz  and  mica,  it  is  found  north  of  Yuma 
in  the  form  of  small  stout  crystals  about  one-half  inch  in 
length.  In  the  same  locality  it  is  further  found  associated 
with  dumortierite. 

Epidote,  HCa2(Al,Fe)3Si3013 

This  mineral  is  a  silicate  of  calcium,  iron  and  alumin- 
ium, and  can  usually  be  easily  recognized  by  its  pecul- 
iar yellowish  green  color.  It  is  abundantly  developed  in 
Arizona  as  the  result  of  contact  metamorphism  ;  hence  it 
is  found  associated  with  garnet  and  other  products  of  this 

1  Ransome  :  U.  S.  G.  S.,  PP.  No.  12,  p.  66. 


OXYGEN   SAI,TS  65 

action  in  most  of  the  mining  districts.  It  is  further  formed 
as  the  result  of  other  secondary  decomposition  in  nearly 
all  kinds  of  rocks,  both  sedimentary  and  volcanic.  It  may 
appear  as  greenish  incrustations  on  the  surface  of  rocks 
or  as  filling  in  minute  cracks.  In  the  Tucson  mountains 
it  has  been  observed  as  a  decomposition  product  in  light 
colored  rhyolites  where  it  appears  as  green  blotches 
through  the  specimen.  Some  of  the  spots  are  rather  an- 
gular and  are  thought  to  be  pseudomorphs  after  feldspar. 
In  the  same  locality  it  is  found  in  dark  andesitic  rocks,  as 
thin  incrustations  along  the  joint  planes.  This  mineral 
being  of  such  wide  occurrence  is  usually  found  in  the 
streams  and  washes  as  greenish  pebbles,  and  as  green 
stains  on  other  fragments.  The  association  of  epidote 
and  native  copper  has  been  described  under  Copper. 

Gadolinite 

This  is  a  silicate  of  glucinum,  iron,  the  rare  yttrium 
earths,  and  cerium.  It  is  quite  abundant  in  the  mineral- 
ized pegmatites  of  Norway  and  Sweden,  but  extremely 
rare  elsewhere.  In  Texas  it  has  been  found  in  nodular 
masses  and  rough  crystals  of  large  size.  In  1908  a  de- 
posit was  found  near  Kingman,  Arizona,  and  several  tons 
of  the  material  have  already  been  shipped  East  for  the 
extraction  of  rare  earths  employed  in  the  preparation  of 
the  well-known  mantles  for  incandescent  gas  light.  The 
mineral  from  this  locality  presents  the  usual  appearance 
of  dark  brown  to  black  glassy  masses  of  conchoidal 
cleavage  not  unlike  ordinary  obsidian.  It  has,  however, 
a  very  much  higher  density.  It  occurs  associated  with 


66  THE    MINERALOGY    OF    ARIZONA 

the  new  mineral,  arizonite,  in  what  seem  to  be  pegma- 
tites. Mr.  Chase  Palmer  has  made  a  partial  analysis, 
the  results  of  which  are  given  below.1 

Per  cent. 

SiO2    24.41 

Yttrium  earths 36.86 

Cerium  earths 11.50 

BeO 11.50 

FeO 11.56 

Calamine,  H2ZnSi05 

The  hydrous  silicate  of  zinc,  or  calamine,  has  been  re- 
ported as  occurring  in  minute  quantities  on  garnet  rock 
in  the  Shannon  mine  in  the  Clifton-Morenci  districts.2 
Tourmaline 

This  is  a  complex  silicate  of  boron,  aluminium  and  sim- 
ilar elements.  As  stout  black  hexagonal  crystals,  some- 
times bent  and  faulted  it  is  found  in  the  Catalina  moun- 
tains near  Oracle.  It  is  here  occasionally  disseminated 
through  the  mass  in  such  a  manner  as  to  constitute  a 
typical  tourmaline  granite.  It  is  not  found  in  large 
masses,  however,  and  is  simply  a  local  condition  along 
the  borders  of  the  main  granitic  material.  A  microscopic 
examination  shows  it  to  be  associated  with  quartz,  plagi- 
oclase,  orthoclase  and  microcline.  Tourmaline  seems 
to  be  very  widely  distributed  throughout  the  State  as 
shown  by  the  frequent  samples  received  for  identification 
at  the  University  of  Arizona.  Among  these  have  been 
observed  frequently  fibrous  and  even  granular  modifica- 
tions of  the  mineral. 

1  Am.  Jour.  Sci.,  28,  353. 

*  Lindgren  :  U.  S.  G.  SM  PP.  No.  43,  p   in. 


OXYGEN   SAI/TS  67 

Dumortierite 

This  is  a  rare  silicate  of  aluminium  with  a  small  per 
cent,  of  boron.  It  is  of  a  beautiful  blue  color  and  has  fre- 
quently been  mistaken  for  copper  minerals.  It  is  fre- 
quently found  in  the  form  of  float  or  loose  rounded  peb- 
bles in  the  vicinity  of  Clip,  north  of  Yutna.  It  is  asso- 
ciated with  rather  granular  quartzite-like  rock  highly 
metamorphic  and  sometimes  so  intimately  mixed  that 
the  entire  specimen  appears  blue.  Under  the  microscope 
however,  thin  sections  show  that  the  mass  is  made  up  of 
fine  needles  and  bunches  of  radiating  crystals  embedded 
in  the  quartzite.  The  mineral  shows  beautiful  pleocroism, 
the  color  parallel  to  the  elongation  being  a  deep  blue, 
while  the  other  two  directions  give  nearly  colorless  and 
pale  violet.  The  quartz  is  well  crystallized,  appears  in 
rounded  individuals  with  sharp  contacts  and  contains 
numerous  gas  and  liquid  inclusions.  The  gas  bubble  is 
frequently  found  to  be  in  motion.  The  mineral  from 
Clip  has  been  analyzed  by  Diller1  and  Ford2  both  of  whom 
found  noticeable  quantities  of  boron  oxide.  These  analy- 
ses are  of  value  since  they  show  that  the  mineral  is  to  be 
considered  as  a  compound  containing  boron  and  not  a 
simple  silicate  as  formerly.  The  Arizona  locality  is  of  es- 
pecial interest  since  here  the  mineral  seems  to  be  found 
in  a  metamorphic  rock  rather  than  in  pegmatites  the 
more  usual  mode.  The  presence  of  the  gas  inclusions 
prove,  however,  that  the  metamorphism  is  of  a  deep-seated 
type. 

1  Am.  Jour.  Sci.,  3d  series,  37,  p.  216. 
*  Am.  Jour.  Sci.,  4th  series,  14,  p.  426. 


68  THE    MINERALOGY    OF    ARIZONA 

Mica 

There  are  several  varieties  of  mica  varying  in  composi- 
tion and  appearance,  but  all  possessing  the  well-known 
cleavage  and  yielding  elastic  plates. 

Muscovite. — This  variety  is  the  common  white  mica 
and  is  a  frequent  constituent  of  rocks  and  soils.  In  large 
crystals  it  frequently  developes  in  pegmatites  or  the  white 
vein-like  formations  seen  crossing  granite  and  similar 
rock  masses.  It  is  further  a  constituent  of  metamorphic 
schists.  Sericite,  a  closely  allied  variety  has  been  fully 
described  by  Ransome  in  the  schists  of  the  Bisbee  Quad- 
rangle,1 and  by  the  same  author  in  similar  rocks  of  the 
Globe  district. 

Biotite,  or  the  black  mica,  is  similar  in  composition 
with  the  exception  that  it  contains  iron  and  magnesium. 
It  is  abundant  in  Arizona  as  a  rock-forming  mineral  in 
the  biotite  granites,  gneisses  and  metamorphic  schists. 

Doubtless  other  varieties  of  mica  are  to  be  found  in 
Arizona,  but  as  yet  they  have  not  been  investigated. 

Serpentine 

This  is  a  hydrous  magnesium  silicate,  a  secondary 
mineral  resulting  from  the  alteration  of  such  minerals 
as  olivine,  pyroxene,  hornblende,  etc.  Such  rocks  as  the 
peridotites,  which  are  made  up  almost  entirely  of  these 
minerals,  yield  on  disintegration  large  deposits  of  ser- 
pentine. It  is  a  rather  soft  mineral,  usually  of  greenish 
color  and  a  slight  soapy  feel. 

i  u.  s.  G.  s.,  PP.  NO.  21,  p.  25. 


OXYGEN   SALTS  69 

Ordinary  Serpentine.  —  Impure  massive  serpentine  is 
found  associated  with  magnetite  in  the  Dos  Cabesas 
mountains.  A  similar  mode  of  occurrence  has  been  noted 
by  Lindgren  in  the  Clifton-Morenci  district  in  the 
Thompson  mine.1 

Chrysotile  or  Asbestos. — This  is  the  crystallized  or 
fibrous  variety  of  serpentine  and  is  known  on  the 
market  as  asbestos.  It  is  found  in  the  granite  gorge  of 
the  Grand  Canon,  4,000  feet  below  the  rim  on  the  north 
side  of  the  river,  where  it  is  mined  by  the  Hance  Asbes- 
tos Co.  The  fibers  are  of  excellent  quality,  of  good 
length  and  very  flexible.  The  mineral  occurs  in  cracks 
or  seams  in  the  rock  where  the  fibers  have  arranged  them- 
selves perpendicular  to  the  surfaces.  The  asbestos  seems 
to  be  associated  with  limestone  which  has  become  altered 
through  the  contact  action  of  intrusive  diabase.  It  is 
supposed  to  have  resulted  from  the  hydration  of  the 
pyroxenes.  While  the  material  is,  perhaps,  of  the  finest 
quality  of  any  found  in  the  United  States,  its  inaccessi- 
bility makes  it  difficult  to  work  the  deposit  with  profit.2 
Another  locality  has  been  reported  from  a  place  twenty 
miles  west  of  Globe  where  it  occurs  in  seams  in  massive 
serpentine. 

Talc 

This  well-known  mineral  is  also  a  decomposition  pro- 
duct of  ferromagnesium  minerals  and  is  frequently  met 
with  in  the  vicinity  of  mines  where  metamorphic  agencies 
are  at  work.  It  is  lighter  in  color  and  softer  than  ser- 

*U.  S.  G.  S.,  PP.  No.  43. 
2  Mineral  Resources,  1908. 


7O  THE    MINERALOGY    OF    ARIZONA 

pentine.     No  unusual  or  particular  interesting  mode  of 
occurrence  has  been  observed  in  Arizona. 
Kaolinite,  H4A12S1209 

Kaolinite,  or  as  it  is  more  commonly  known,  kaolin  is 
a  secondary  mineral  resulting  from  the  decomposition  of 
feldspathic  minerals.  It  is  consequently  always  found 
where  weathering  and  erosion  are  going  on  and  is  hence 
a  constituent  of  all  soils.  Only,  however,  where  condi- 
tions are  favorable  for  a  sorting  action  in  quiet  water  by 
which  the  fine  clayey  material  is  separated  from  the  sand 
and  gravel,  is  it  found  in  a  comparatively  pure  state  and 
in  quite  large  deposits.  In  Arizona,  the  debris  from  the 
mountains  is  brought  down  by  flood  waters  and  periodi- 
cally spread  upon  the  plain,  a  condition  very  unfavorable 
to  the  formation  of  deposits  of  kaolin  or  clay.  Yet  these 
deposits,  further  worked  over  by  less  flooded  conditions, 
sometimes  give  rise  to  deposits  still  containing  large 
amounts  of  sand,  but  of  sufficient  purity  to  be  used  local- 
ly for  the  manufacture  of  red  brick,  making  it  possible 
for  the  large  towns  of  the  State  to  have  their  brickyards 
where  a  product  of  fair  quality  is  manufactured. 

Pure  Kaolin. — This  is  frequently  met  with  in  the  form 
of  soft  putty-like  masses  in  many  of  the  mines  where  it 
has  resulted  from  a  kaolinization  of  the  feldspars.  In 
the  Clifton-Morenci  district  it  is  reported  as  accompanying 
chalcocite  in  the  porphyry  ;  in  small  veinlets  in  quartz  at 
the  Hombolt,  Ryerson  and  other  mines ;  in  mammillary 
masses  associated  with  azurite  malachite  in  the  I^ong- 

fellow  mine.1     Associated  with  limonite,  it  is  found  in 
i  u.  s.  G.  s.,  PP.  NO.  43. 


OXYGEN    SAI/TS  71 

large  quantities  in  the  Copper  Queen  mines,  where  it  has 
been  selected  and  used  as  a  binding  material  for  the  quartz 
used  in  lining  the  converters. 

Graphitic  Clay. — A  large  deposit  of  this  varietysof  clay 
is  found  about  seven  miles  from  Benson.  It  is  black  and 
closely  resembles  soft  coal.  When  ground  to  a  fine  pow- 
der and  mixed  with  water  it  becomes  very  plastic.  The 
black  color  disappears  on  burning,  the  mass  assuming  a 
buff  color.  The  material  has  been  used  for  the  manufac- 
ture of  pressed  brick  and  is  still  extensively  used  in  con- 
verter plants  as  a  binding  material,  in  Cananea,  Bisbee 
and  other  mining  localities.  The  deposit  is  said  to  be 
almost  unlimited  in  extent.  Its  composition  is  illustrated 
by  the  following  analysis  : 

Per  cent. 

Silica    59.15 

Iron  and  alumina 27. 52 

Calcium  carbonate 2.82 

Water  and  undetermined 10.51 

Cement  Clay. — Doubtless  clays  or  shales  of  good  quali- 
ty for  the  manufacture  of  Portland  cement  could  be  found 
in  many  places  in  Arizona  were  the  field  throughly  pros- 
pected. At  present,  however,  high  freight  rates  and 
small  local  markets  combine  to  make  the  outlook  for  the 
cement  industry  in  Arizona  rather  discouraging.  A 
government  plant  has  been  in  operation  at  Roosevelt 
where  the  product  was  used  for  the  construction  of  the 
Tonto  dam.  The  clay  found  here  has  the  following 
composition  : 


72  THE    MINERALOGY    OF    ARIZONA 


Silica  51.91 

Iron  and  alumina 23.70 

Lime 6. 10 

Magnesia 0.97 

Water 13.40 

Limestone  of  good  quality  to  combine  with  the  clay  is 
found  in  the  immediate  vicinity.1 

The  writer  has  investigated  clay  deposits  in  the  vicinity 
of  Flagstaff  and  found  material  of  very  satisfactory  com- 
position for  the  cement  industry.  Here  it  results  from 
the  decomposition  of  black  basaltic  and  andesitic  rocks 
and  has  collected  in  a  depression  caused  by  a  series  of 
lava  flows  in  what  is  known  as  Rogers  Lake.  The  deposit 
is  about  700  acres  in  extent  and  varies  in  thickness  from 
three  feet  near  the  edges  to  nine  feet  near  the  center.  It 
is  yellowish  grey,  very  tough  and  plastic.  Its  composition 
is  as  follows : 

Per  cent. 

Silica    52.94 

Alumina    1 7.91 

Iron  oxide ••••....     9. 23 

Lime 1.22 

Magnesia  .   0.42 

Alkalies 2.22 

Water,  etc 16.34 


Total 100.28 

A  burning  test  was  made  on  this  material  using  100 
parts  of  clay  to  300  parts  of  limestone.  An  excellent 
quality  of  cement  resulted. 

1  U.  S.  G.  S.,  Bui.  No.  243,  p.  87. 


OXYGEN   SALTS  73 

Chrysocolla,  CuSi03 ,2H20 

This  is  a  light  blue  compact  mineral,  much  resembling 
turquoise,  quite  common  near  the  surface  in  many  of  the 
mines  in  the  State.  In  the  Globe  district  it  is  known 
to  be  very  abundant,  where  it  occurs  in  veinlets  in  im- 
pure cuprite,  in  mineralized  porphyry,  and  in  associated 
oxidized  minerals.  Very  beautiful  samples  are  some- 
times found  in  which  the  delicate  blue  mammillary 
masses  are  covered  with  thin  crusts  of  drusy  quartz  crys- 
tals. The  mineral  as  found  in  the  mines  is  much 
harder  than  expected  from  the  descriptions  in  the  text- 
books. This  is  because  of  the  silicious  matter  pres- 
ent as  impurities;  in  fact,  a  great  deal  of  the  material 
thought  to  be  chrysocolla  is  in  reality  quartz  or  silica 
stained  with  copper  minerals. 

Lettsomite 

This  is  a  rare  silicate  of  copper  and  aluminium.  The 
mineral  is  sky-blue,  fibrous  and  possesses  a  silky  luster. 
It  has  been  found  in  a  silicious  rock  in  Arizona  in  the 
form  of  small  seams.1 


(3)  PHOSPHATES,  VANADATES,  ETC. 

Apatite,  CaFl,  Ca4(P04)3 

This  is  found  as  a  universal  microscopic  accessory  in 
both  granitic  and  eruptive  rocks.  It  appears  as  minute 
colorless  needles,  sometimes  tufts,  but  more  often  as 
isolated  crystals  in  the  more  basic  constituents  of  the 

1  Genth  :  Am.  Jour.  Sci.  3d  series,  4,  p.  119. 


74  THE    MINERALOGY    OF    ARIZONA 

rock.       As  shown  by  chemical  analysis,   it  is  probably  a 
constituent  of  all  soils,    its  ultimate   origin   being   the 
microscopic  crystals  mentioned  above. 
Ecdemite 

This  rare  chloro-arseniate  of  lead  has  been  observed  as 
soft  drusy  incrustations  on  wulfenite  crystals  from  the 
Mammoth  mine  in  the  Catalina  mountains.  It  is  of  an 
orange  color,  about  the  same  tint  as  the  wulfenite,  and  can 
hardly  be  distinguished  from  it.  Under  the  microscope, 
however,  the  crystallization  can  easily  be  distinguished. 

Mimetite 

This  also  is  a  rare  chloro-arseniate  of  lead  appearing 
usually  as  pale  yellow  incrustations  consisting  of  rounded 
aggregates.  It  has  been  reported  from  a  locality  a  few 
miles  northwest  of  the  Vulture  mine.1 

Vanadinite,  PbCl,  Pb4(VoJ3 

This  rare  and  beautiful  mineral  is  frequently  met  with 
in  Arizona,  particularly  in  quartz  veins  carrying  gold 
and  silver.  In  composition  it  is  a  chloro-vanadate  of 
lead,  and  ordinarily  can  be  easily  recognized  by  its 
hexagonal  crystallization  and  its  striking  red  color.  It 
generally  appears  as  incrustations  and  isolated  implanted 
crystals,  sometimes  barrel  shaped,  but  more  often  of  good 
hexagonal  development.  It  is  found  in  the  cavities  of 
the  vein  filling  material,  a  fact  which  proves  that  it  was 
deposited  during  the  last  stages  of  mineralization.  It  is 
sometimes  found  even  encrusting  calcite.  Important 
localities  in  Arizona  are  the  Red  Cloud  mine,  Yurna  Co., 

*  Am.  Jour.  Sci.,  3d  series,  aa,  p.  202. 


OXYGEN   SALTS  75 

the  Mammoth  mine  at  Schulz,  in  the  Catalina  mountains, 
Pima  Co.,  and  the  OldYuma  mine,  about  14  miles  north- 
west of  Tucson.  Minerals  which  are  most  often  asso- 
ciated with  it  are,  wulfenite,  cerussite,  ecdemite  anddes- 
cloisite.  In  the  Globe  district,  where  it  is  also  quite 
common,  it  occurs  along  prominent  fault  fissures  in  the 
Apache  quartzites.1  In  all  of  these  cases  the  mineral  is 
found  filling  cavities  and  seams  in  the  country  rock  in 
the  immediate  vicinity  of  the  vein  as  well  as  in  the  vein 
itself.  This  is  especially  true  of  the  deposit  in  the  Yuma 
mine  where  good  vein  filling  has  progressed  to  only  a 
limited  extent.  Here  the  vanadinite  and  associated  min- 
erals may  be  found  implanted  on  the  surface  of  planes 
formed  by  fractures  in  the  country  rock.  Fine  museum 
specimens  are  sometimes  found  which  consist  of  a  slab  of 
the  country  rock  first  covered  with  a  layer  of  calcite,  then 
vanadinite  and  finally  a  thin  layer  of  descloisite.  Crys- 
tals have  been  found  over  one-fourth  inch  in  diameter. 

The  origin  of  this  mineral  or  the  chemical  changes 
which  have  been  concerned  in  its  production  are  points 
which  have  not  yet  been  worked  out.  Dr.  Hillebrand 
has  called  attention  to  the  wide  distribution  of  vanadium 
in  the  rocks  of  the  United  States,2  and  the  universal 
occurrence  of  apatite  with  which  this  mineral  is  isomor- 
phous,  as  microscopic  accessories  in  rocks,  is  well-known. 
It  may  be  possible  then  that  the  mineral  originally  ex- 
isted in  minute  traces  in  the  apatite  molecule  in  which 
case  the  mineral  might  easily  become  concentrated  by 

1  C.  F.  Tolman  :  Private  Communication. 

2  U.  S.  G.  S.,  Bui.  No.  305,  p.  19. 


76  THE    MINERALOGY    OF    ARIZONA 

simple  solution,  without  the  intervention  of  complex 
chemical  reactions.  The  mineral,  however,  has  been 
produced  artificially  by  Weinschenk1  by  bringing  to- 
gether, at  moderately  high  temperatures,  chloride  of  lead 
and  vanadium  compounds.  This  investigation  would 
seem  to  show  that  if  the  vanadium  originally  existed  in 
the  complex  basic  silicate  molecule,  reactions  with  lead 
chloride  could  take  place  which  would  give  rise  to  the 
mineral. 

Libethenite,  Cu3P208,  Cu(OH)2. 

This  is  a  green  basic  phosphate  of  copper.  In  has  re- 
cently been  found  in  the  Coronado  mine  in  the  Clifton- 
Morenci  district,  as  small  olive-green  crystals  less  than 
one  millimeter  in  length.  It  is  associated  with  quartz 
and  needles  of  malachite.  The  mineral  was  identified  by 
Professor  Penfield  of  Yale  and  the  Caronado  mine  is 
probably  the  only  known  locality  containing  it  it  the 
United  States.5 

Descloisite  and  Cupro-descloisite 

These  minerals  are  basic  vanadates  of  lead  and  zinc 
usually  containing  varying  quantities  of  copper  and  man- 
ganese. In  Arizona  they  are  nearly  always  found  asso- 
ciated with  wulfenite  and  vanadinite.  The  most  char- 
acteristic appearance  is  that  of  lustrous  bronzy  or  black 
incrustations  rarely  more  than  one  or  two  millimeters  in 
thickness.  In  some  cases  the  appearance  is  very  much 
like  that  of  thin  varnish  on  the  surface  of  other  minerals. 

1  Brauns  :  Chemische  Mineralogie,  p.  270. 

2  U.  S.  G.  S. ,  PP.  No.  43. 


OXYGEN   SAWS  77 

They  are  found  deposited  on  calcite,  wulfenite  and 
vanadinite  crystals,  and  hence  are  deposited  later.  Well- 
known  localities  in  Arizona  are  the  Castle  Dome  district, 
Tombstone,  Mammoth  mine  in  the  Catalina  mountains, 
and  the  Old  Yum  a  mine  in  the  Tucson  range  of  moun- 
tains. The  writer  has  analyzed  this  mineral  from  two 
widely  different  localities,  the  results  of  which  are  given 
below.  No.  i  was  from  the  Old  Yuma  mine  in  the 
Tucson  mountains,  and  No.  2  from  the  Argentine  Repub- 
lic. No.  i  appeared  as  crystalline  incrustations  on  crys- 
tals of  vanadinite.  These  were  chosen  in  preference  to 
the  incrustations  found  on  calcite  for  the  reason  that  it 
was  believed  that  possible  contamination  from  this  source 
would  not  be  so  serious  as  from  the  calcite.  No.  2  ap- 
peared as  distinct  orthorhombic  crystals  about  two  milli- 
meters in  length.  Analysis  No.  2  was  conducted  in  the 
Fresenius  Chemical  Laboratories  in  Wiesbaden,  and 
recognition  is  due  Dr.  H.  Fresenius  and  Dr.  W.  Fresenius 
for  permission  to  carry  on  the  investigation  as  well  as 
valuable  suggestions  regarding  the  method  of  analysis. 

No.  I  No.  2 


Ratios  Per  cent.  Ratios 

Cl 0.08 

Insoluble..    0.78 

As2O5 o.  i  r 

PbO 52.26  0.2345            53.36  0.2393 

CuO 11.64  0.1462               i. 21  0.0152 

FeO    0.56  0.0077 

ZnO 6.71  0.0824            13.15  0.1615 

MnO    2.16  0.0304              4.56  0.0642 

V2O5 23.02  0.1262             23.05  0.1263 

H2O    2.52  0.1400               2.27  0.1261 

Total 98.31  99-13 


78  THE    MINERALOGY    OF    ARIZONA 

Reduced  to  simpler  terms,  these  ratios  become : 

No.  i  No.  2 

RO 0.4935  =  4  0.4879  =  4 

V2O5 o.  1262  =  i  o.  1263  =  i 

H2O 0.1400=1  0.1261^1 

The  formula  then  becomes  (RO)4.  V2O5.  H2O,  or, 
R3(VO4)2.  R(HO)2,  which  is  that  usually  given  to  this 
mineral. 

The  method  of  analysis  briefly  outlined  is  as  follows  : 
The  finely  divided  mineral  is  dissolved  in  strong  nitric 
acid,  diluted  and  the  insoluble  residue  filtered  off,  ignited 
and  weighed.  In  the  filtrate,  chlorine  is  determined  by 
means  of  a  standard  solution  of  silver  nitrate.  The  silver 
chloride  is  filtered  off  after  adding  a  few  drops  of  chlor- 
hydric  acid  to  precipitate  excess  of  silver  used  in  titration. 
The  lead  is  then  precipitated  with  H2SO4,  removed  and 
weighed.  The  filtrate  is  now  evaporated  to  dryness  to 
remove  nitric  acid.  Any  further  precipitate  of  lead  sul- 
phate is  filtered  off  and  weighed.  The  solution,  properly 
diluted,  is  now  precipitated  with  H2S,  the  precipitate  dis- 
solved in  nitric  acid  and  reprecipitated.  It  is  then  dis- 
solved again  and  the  copper  determined  iodometrically. 
The  two  filtrates  from  the  H2S  precipitation  are  combined, 
oxidized  with  nitric  acid,  and  the  iron,  manganese  and 
zinc  separated  from  vanadium  by  precipitation  with 
sodium  carbonate  twice  repeated  (three  precipitations). 
The  three  filtrates  containing  vanadium  are  combined, 
evaporated  with  H2SO4  to  remove  nitric  acid,  diluted  and 
reduced  with  H,S.  After  removal  of  H2S  by  boiling  and 
passing  in  CO2,  the  vanadium  is  determined  by  titration 


OXYGEN  SAI/TS  79 

with  a  standard  solution  of  permanganate.  The  precipi- 
tate of  iron,  zinc  and  manganese  is  now  dissolved  in  HC1 
and  precipitated  with  NH4OH,  the  precipitate  redissolved 
and  a  basic  carbonate  precipitation  of  iron  made  with  am- 
monium carbonate.  The  precipitate  is  again  dissolved  and 
precipitated  with  NH4OH.  The  iron  is  then  ignited  and 
determined  in  the  usual  wa}'.  The  three  filtrates  con- 
taining manganese  and  zinc  are  combined,  the  zinc  precip- 
itated with  H2S  in  a  very  slightly  acid  solution  (with 
H2SOJ ,  filtered  off  and  ignited  in  a  Rose  crucible  with 
hydrogen.  The  manganese  is  then  precipitated  with 
(NHJ2S  in  an  alkaline  solution  and  the  MnS  ignited  in 
the  same  manner  as  the  zinc. 

Erythrite,  Co3As208.8H20 

This  mineral  is  sometimes  known  as  cobalt  bloom  on 
account  of  its  delicate  flower-like  tint  and  frequent  radi- 
ating structure.  It  is  a  very  rare  mineral  but  has  recently 
been  discovered  near  Jerome  where  it  occurs  as  soft 
powder-like  incrustations  on  a  dark  colored  gangue  con- 
taining disseminated  grains  of  cobaltite.  It  is  of  a  delicate 
pink  color  as  usual  but  good  crystallizations  have  not 
been  observed.  The  deposit  is  being  exploited  for  the 
cobalt  and  already  some  of  the  ore  has  been  shipped  to 
New  Jersey  for  treatment.  Accurate  information  regard- 
ing the  mode  of  occurrence  and  associations  has  not  yet 
been  obtained. 

Turquoise 

Mineralogically  this  gem  mineral  is  a  phosphate  of 
alumina  and  copper.  Because  of  its  delicate  blue  color 


8O  THE    MINERALOGY    OF    ARIZONA 

it  has  been  highly  prized  by  the  prehistoric  people  of 
western  United  States  and   Mexico.     It   is,    therefore, 
found  in  many  of   the  Aztec  ruins  in  Mexico  and  in 
ruins,  of  perhaps  similar  origin,  in  Arizona.     It  is  found 
in  situ  in  the  Dragoon  mountains,  on  the  road  between 
Pearce  and  Gleason,  where  it  occurs  in  a  greatly  decom- 
posed rock,  perhaps  a  kaolinized  rhyolite,  in  the  form  of 
irregular  patches   and  veinlets.     When   these   deposits 
were  first  discovered,  there  were  abundant  evidences  of 
mining  in  a  crude  way,    doubtless  the   work   of  some 
Indian  tribe  or  of  a  prehistoric  people.  Some  implements 
were  found  and  evidences  of  the  use  of  fire  employed, 
perhaps,  for  the  purpose  of  breaking  up  the  rock.     An- 
other important  locality  is  in   Mineral    Park,    Mohave 
County.     During  the  last  two  or  three  years  this  dis- 
trict has  produced  considerable  material  for  the  market. 
Several  mining  companies  are  operating  in  the  district, 
among  which  may  be  mentioned  the  Arizona  Turquoise 
Co.,  Los  Angeles  Gem  Co.,  Southwest  Turquoise  Co., 
and  the  Aztec  Turquoise  Co.     The  deposit  is  found  in 
certain  hills  along  the  west  side  of  the  Cerbat  range  of 
mountains,  consisting  chiefly  of  gneisses  and  schists  cut 
by  later  granites  and  porphyries.     Is  is  in  these  latter 
porphyries  that  the  gem  material  is  found.     The  porphyry 
is  greatly  decomposed  in  the  vicinity  of  the  turquoise. 
It  would  appear  that  some  of   the  turquoise  has  been 
formed  directly  from  the  kaolinized  material  by  the  ad- 
dition of  copper  and  phosphated  material.     Gradations 
are  observed   between  simply  copper  stained  kaolin  to 


OXYGEN   SALTS  8 1 

pure  turquoise.  An  interesting  specimen  was  recently 
cut  by  the  Los  Angeles  Co.,  which  consisted  of  the  letter 
Y  in  blue  in  a  gray  matrix.  It  was  formed  by  the  inter- 
section of  two  small  veinlets.  The  stone  was  sent  to  a 
student  at  Yale.1 

Nitre,  KN03 

This  well-known  compound  is  frequently  formed  on 
old  wall,  in  caves,  and  on  the  side  of  mine  shafts,  usually 
however,  in  such  small  quantities  as  to  escape  obser- 
vation. It  is  even  said  to  develop  in  old  morters  to  the  ex- 
tent of  5  per  cent.2  The  writer  has  observed  it  associated 
with  sodium  carbonate  as  a  thin  white  covering  on  the 
surfaces  of  the  overhanging  limestone  shelves  in  the 
ancient  cliff-dwellings  of  Walnut  Canon,  about  twelve 
miles  from  Flagstaff.  The  walls  of  the  canon  here  are 
made  up  of  layers  of  soft  and  hard  limestone,  or  more 
appropriately  calcareous  sandstone,  which  has  disinte- 
grated, yielding  a  series  of  shelves  that  have  been  very 
conveniently  utilized  as  dwellings  by  the  ancient  inhabi- 
tants of  Arizona. 

Nitrocalcite 

This  is  a  hydrous  nitrate  of  calcium  sometimes  met 
with  in  limestone  caves,  where  doubtless  an  interaction 
has  taken  place  between  the  calcium  carbonate  and  bat 
guano  or  other  organic  compounds.  A  bacteriological 
action  may  also  be  concerned  in  its  formation  more  or 
less  direct  from  the  atmosphere.  It  has  been  reported 

1  Mineral  Resources,  1908. 

2  Dana  :  System  of  Mineralogy. 


82  THE:    MINERALOGY    OF    ARIZONA 

as  occurring  in  the  Mammoth  Cave  in  Kentucky.  A 
sample  of  this  mineral  mixed  with  a  large  quantity  of 
earth  was  received  at  the  University  of  Arizona  during 
the  summer  of  1907  and  indentified  as  calcium  nitrate  by 
Dr.  A.  E.  Vinsonof  the  Agricultural  Experiment  Station. 
Correspondence  with  the  sender  of  the  sample  brought 
the  following  interesting  information:  "The  calcium 
nitrate  occurs  in  vents  in  the  Lower  Carboniferous  Lime- 
stone, fissures  that  cut  across  the  bedding  planes  and  are 
therefore  perpendicular.  There  are  several  of  these  vents 
grouped  close  together  exposed  to  full  view  in  the  railroad 
cut  facing  the  Gila  river  about  two  miles  above  Winkel- 
man.  The  face  at  this  spot  is  a  sheer  wall  about  100  feet 
high  and  the  vents  filled  with  the  nitrate  are  visible  from 
top  to  bottom.  None  of  them  are  more  than  6  to  8  inches 
wide  and  the  nitrocalcite  seems  to  be  mixed  with  red 
iron."  ' 

Gerhardite 

This  is  a  basic  copper  nitrate  found  as  a  coating  of  dull 
green  color,  on  the  cliffs  in  the  Clifton-Morenci  district. 
It  is  supposed  to  have  been  formed  through  the  action 
of  atmospheric  water  on  copper  salts.2  It  is  also  found  in 
the  Jerome  district  associated  with  cuprite  and  malachite. 
(Dana.)  It  is  a  very  rare  mineral  and  is  never  found 
except  as  thin  coatings  or  stains  on  other  minerals. 

Colemanite,  Ca2B6On.  5H20 

An  extraordinary  occurrence  of  this  mineral  has  been 

1  Private  communication  from  Mr.  K.  B.  Zachn,  Winkelman,  Arizona. 

2  U.S.  G.  S.,  PP.  No.  43- 


OXYGEN   SAI/TS  83 

reported  by  Morgan  and  Tallmon.1  It  is  found  asso- 
ciated with  a  tar-like  substance  in  a  fossil  egg  found  in 
the  placer  deposits  of  the  Gila  River. 


(4)  SULPHATES 

Thenardite,  Na2S04 

This  mineral  is  the  sulphate  of  sodium  and  usually  ap- 
pears as  a  dull  yellow  substance  soluble  in  water.  It  is 
found  in  large  deposits  in  the  Verde  Valley,  Yavapai  Co. , 
near  Camp  Verde,  where,  mixed  with  halite,  it  is  said  to 
have  been  used  as  a  substitute  for  salt  for  cattle  and  horses. 
The  deposit  is  several  acres  in  extent  and  fifty  or  more  feet 
in  depth.  It  is  very  compact,  mingled  with  clay,  and 
associated  with  Mirabilite,  halite  and  glauberite.2 

Glauberite,  Na2S04,  CaS04 

This  mineral  resembles  the  one  just  described  but  differs 
from  it  in  containing  calcium  sulphate  in  addition  to 
sodium  sulphate.  As  stated  above  it  is  found  in  the  Verde 
Valley  associated  with  other  soluble  sulphate  and  chlo- 
rides. 

Barite,  BaSO, 

Barite,  or  the  sulphate  of  barium,  is  commonly  known 
as  heavy  spar  because  of  its  high  specific  gravity.  It 
occurs  most  often  as  a  gangue  mineral,  accompanying 
such  sulphides  as  galena,  iron  pyrite,  etc.  It  is  usually 
nearly  white  in  color  and  quite  soft.  In  the  Silver  Bell 

1  Am.  Jour.  Sci.,  18,  363. 

2  W.  P.  Blake,  Am.  Jour.  Sci.,  3d  series,  39,  p.  44. 


84  THE    MINERALOGY    0*    ARIZONA 

district,  barite  is  found  as  lustrous  white  aggregates  of 
crystals  associated  with  blue  cubes  of  fluospar.  In  the 
Quiotoa  district  it  is  found  in  large  masses,  which  on  dis- 
integration, yield  aggregates  of  disk  or  shell-like  shapes. 
They  closely  resemble  shells  which  have  been  cemented 
together.  They  are  sometimes  covered  with  drusy  crys- 
tals of  calcite,  siderite,  or  other  similar  minerals.  It  has 
further  been  observed  in  white  seams  in  blue  limestone 
west  of  the  Tucson  range  of  mountains,  in  the  properties 
south  of  the  San  Xavier  Mission,  associated  with  argen- 
tiferous galena,  and,  in  fact,  associated  with  a  variety  of 
minerals  in  many  of  the  mines  of  the  State. 

Anglesite,  PbS04 

This  is  the  sulphate  of  lead  and  represents  the  first 
stage  in  the  alteration  of  galena  by  which  cerussite  is 
finally  produced.  It  being  an  intermediate  product,  it 
is  of  rarer  occurrence  that  the  carbonate,  cerussite. 
When  pure  it  is  white  and  transparent,  but  more  often 
appears  as  massive  varieties  with  yellow,  gray  or  nearly 
black  shades.  Samples  from  the  Castle  Dome  district  have 
been  described  and  analyzed  by  Professor  Brush.1  An  in- 
teresting modification  of  this  mineral  came  to  the  writer's 
notice  several  years  ago.  The  specimen  came  from  the 
Tombstone  district  and  exhibited  pseudomorphous  struc- 
ture after  galena.  The  sample  weighed  several  pounds 
and  originally  consisted  evidently  of  an  aggregate  of 
cubic  crystals.  These  have  altered  to  the  sulphate  in 
successive  stages,  giving  rise  to  an  appearance  that  can 

1  Am.  Jour.  Sci,  sd  series,  5,  p.  421. 


OXYGEN   SAI/TS  85 

best  be  described  as  alligator-skin  structure.  The  succes- 
sive layers  about  the  original  galena  granule  varied  in 
color  from  nearly  white  to  dark  gray.  Small  slabs  sawed 
from  this  specimen  present,  when  polished,  a  very  pleas- 
ing and  striking  appearance. 

Crocoitc,  PbCrO, 

Chromate  of  lead  is  of  rather  rare  occurrence  in  nature. 
It  appears  as  bright  red  crystals  and  incrustations  very 
much  resembling  vanadinite,  but  tetragonal  in  crystalliza- 
tion. It  is  found  in  the  Vulture  district  associated  with 
wulfenite  and  vanadinite.  As  shown  by  qualitative  tests, 
it  seems  to  be  quite  frequently  mixed,  isomorphously 
perhaps,  with  wulfenite,  and  in  fact  may  be  the  cause  of 
the  deep  color  of  many  specimens.  Samples  from  the 
Mammoth  mine  in  the  Catalina  mountains  seem  to  show 
a  specially  large  amount  of  chromium. 
Vauquelinite 

This  very  rare  phospho-chromate  of  lead  has  been  re- 
ported from  the  Vulture  district,  where  it  is  associated 
with  crocoite  and  other  lead  minerals. 
Spangolite 

This  is  a  basic  sulphate  of  copper  and  alumina  with 
some  chlorine.  It  is  found  in  very  small  quantities  in 
the  Metcalf  mine  of  the  Clifton-Morenci  district  in  the 
form  of  bluish  flakes  and  hexagonal  incrustations  in 
sericitized  granite-porphyry,  associated  with  cuprite, 
brochantite  and  chrysocolla.1  It  has  also  been  reported 
from  the  Tombstone  district. 

i  Undgren  :  U.  S.  G*  SM  PP.  No.  43. 


86  THE    MINERALOGY    OF    ARIZONA 

Connellite 

This  is  a  rare  chlor-sulphate  of  copper  of  very  complex 
composition  originally  occurring  at  Cornwall.  It  has 
recently  been  discovered  in  Arizona  in  the  Calumet  and 
Arizona  mine  in  Bisbee.  It  is  described  as  associated 
with  melanochalcite  and  chalcophyllite.  It  was  found  as 
dark  blue  radiating  crystals  the  largest  of  which  was  0.5 
millimeters  in  length.  The  mineral  was  analyzed  with 
the  following  results  :l 

Per  cent. 

S08 3.43 

Cl 6.37 

CuO   75.95 

H2O 15.07 

Less  O  —  Cl 1.42 


Total 100.40 

Brochantite,  CuS04,  3Cu(OH)2 

Many  of  the  green  pulverulent  minerals  of  copper,  abun- 
dant in  the  mines  of  northern  Mexico  and  Arizona  and 
usually  classified  by  the  miners  as  malachite,  have  recently 
been  proved  to  be  the  basic  sulphate  of  copper  or  bro- 
chantite.  Mr.  Fred  Hawley,  a  student  in  the  University 
of  Arizona  together  with  the  writer  has  investigated  the 
chemical  and  mineralogical  composition  of  these  ores  from 
the  Cananea  (Mexico)  mines  and  found  that  they  cor- 
respond quite  close  to  the  required  formula.  Mr.  Haw- 
leys  analytical  results  were  as  follows  : 

*  Palache  and  Merwin:  Am.  Jour.  Sci    28,  p.  537. 


OXYGEN   SAl/CS  87 

CuO    59-00 

SO8 17-40 

H2O 10.70 

A12O3 720 

FeO  and  CaO Traces 

SiO2 5.70 

The  alumina  and  silica  are  doubtless  due  to  admixtures 
of  kaolin,  a  mineral  with  which  this  compound  is  fre- 
quently associated. 

Mr.  lyindgren  has  noted  brochantite  in  quite  large 
quantities,  associated  with  malachite,  in  the  Clifton- 
Morenci  district,  and  Mr.  Ransome  in  the  Copper  Queen 
mines  at  Bisbee.1 

Leadhillite,  2PbS04,  H2CO, 

A  rarecarbono-sulphate  of  lead  closely  resembling  cerus- 
site  occurring  at  Schulz,  Final  Co.  (Dana's  Text-book.) 

Mirabilite,  Na2S04,  ioH20 

This  is  a  soluble  sulphate  of  soda  found  in  the  Verde 
Valley,  associated  with  thenardite  and  other  soluble  min- 
erals. It  seems  to  overlie  the  deposit  and  penetrate  it  in 
the  form  of  veinlets.2  It  has  also  been  observed  as  a 
white  incrustation  in  the  basalt  caves  near  Sunset  Peak, 
about  fifteen  miles  from  Flagstaff.  (See  Ice  Caves.) 
Gypsum,  CaS04,  2  H20 

Gypsum  is  a  very  common  mineral  and,  when  favorably 
located,  is  of  commercial  value  in  the  manufacture  of  plas- 
ters. When  burned  at  proper  temperatures  it  develops 
the  property  of  combining  again  with  water  and  forming 

1  U.  S.  G.  S.,  PP.  Nos.  21  and  43. 

2  W.  P.  Blake  :  Am.  Jour.  Sci.,  3d  series,  39,  p.  44. 


88  THE    MINERALOGY    OF    ARIZONA 

a  hard  compact  mass.  This  property  is  called  '  'setting' 
and  the  raw  burned  material  as  well  as  the  final  product 
is  well  known  as  "  plaster  of  Paris ".  Gypsum  occurs  in 
nature  in  three  well-known  varieties :  the  fine  grained 
white  modification  or  alabaster,  the  transparent  variety 
which  easily  breaks  up  into  thin  plates,  or  selenite,  and 
the  fibrous  variety  or  satin  spar.  Gypsum  is  slightly 
soluble  in  water  and  since  it  results  in  the  disintegration 
of  nearly  all  rocks,  through  the  oxidation  of  sulphides 
and  interaction  with  calcium  compounds,  it  is  always 
found,  in  greater  or  less  quantities,  in  natural  waters. 
In  arid  regions  like  Arizona  it  is  apt  to  be  present  in  un- 
usually large  proportions.  Where  circulating  water  is  not 
sufficiently  abundant  to  carry  the  material  away,  it  is 
deposited  as  a  crystallized  mineral  in  the  form  of  impure 
gypsum.  It  is  consequently  very  frequently  met  with  in 
mines  where  sulphides  are  oxidizing  and  reacting  with 
limestone,  and  where  underground  water  is  scarce. 
Although  abundant  oxidation  has  taken  place  in  the  Bisbee 
district,  gypsum  is  entirely  absent  there  because  of  the 
transporting  action  of  large  volumes  of  underground 
water.1  In  the  Clifton-Morenci  district  where  under- 
ground waters  are  less  abundant  it  is  of  more  common 
occurrence.3  These  deposits,  of  course,  are  not  of  sufficient 
size  to  be  of  commercial  value,  but  are  interesting  from 
the  fact  that  they  throw  light  upon  the  chemical  reac- 
tions taking  place  in  connection  with  the  deposition  of 
the  ore  bodies.  Deposits  of  commercial  value  are  formed 

i  Ransome  :  U.  S.  G.  S.,  PP.  No.  21. 
*  I^indgren  :  U.  S.  G.  S.,  PP.  No.  43. 


OXYGEN    SALTS  89 

through  the  evaporation  of  a  lake,  pond  or  arm  of  the 
sea.  These  beds  are  therefore  frequently  depositories  of 
common  salt,  and  other  soluble  minerals.  Hence  it  is 
found  in  the  Verde  Valley  associated  with  thenardite, 
glauberite  and  allied  minerals.  Other  places  where  it  has 
been  locally  used  for  the  manufacture  of  plaster,  are  the 
low  hills  along  the  San  Pedro  valley,  in  Fort  Apache 
Reservation,  Navajo  County,  in  the  Tucson  Valley,  and 
near  Woodruff  and  Snowflake  in  the  northern  part  of  the 
State. 

Epsomite,  MgS04,  7H20 

As  the  name  indicates  this  mineral  is  the  natural  Epsom 
salt  or  magnesium  sulphate.     It  has  been  observed   as 
delicate  moss-like  efflorescences  on  the  walls  of  old  tun- 
nels in  the  mines  of  the  Clifton-Morenci  district.1 
Goslarite,  ZnS04,  7H20 

This  is  the  soluble  sulphate  of  zinc.  It  has  been  ob- 
served in  the  Clifton-Morenci  district  in  exactly  the  same 
mode  of  occurrence  as  epsomite  just  described.  It  results 
from  the  oxidation  of  zinc  sulphide  and  being  soluble  is 
transported  and  deposited  by  the  evaporation  of  percolat- 
ing water. 

Linarite,  (Pb,Cu)S04,  (Pb,Cu)(OH), 

This  beautiful  and  rare  mineral  is  found  in  the  Mam- 
moth-Collins mine  at  Schulz,  Pinal  Co.,  associated  with 
cerussite,  wulfenite  and  other  lead  minerals.  It  is  deep 
blue  in  color  and  when  mingled  with  pure  white  ce- 
russite which  is  also  of  adamantine  luster,  presents  an  ap- 

1  U.  S.  G.  S.,  PP.  No.  43,  p.  121. 


9O  THE    MINERALOGY    OF    ARIZONA 

pearance  of  unusual  beauty.  The  crystallization  is  mono- 
clinic,  but  only  one  crystal  perfect  enough  to  measure 
on  the  reflecting  goniometer  has  been  found.  The  fol- 
lowing faces  were  indentified  :  —  a,  (100),  c,  (101),  s, 
(ooi),  y,  (201),  u,  (101),  w,  (212),  m,  (no),  and  r, 

(in). 

Chalcantite,  CuS04,  sH20 

This  is  the  well-known  blue  vitriol  or  blue  stone.  As  a 
mineral  it  is  frequently  met  with  in  copper  mines, 
especially  in  old  workings,  where  it  is  frequently  found 
in  incrustations  on  old  timbers  and  the  sides  of  the  tun- 
nels, as  well  as  in  the  form  of  stalactites  hanging  from 
the  roofs  of  cavities  and  workings.  In  some  of  the  old 
tunnels  of  the  mines  in  the  Clifton- Morenci  district  it  is 
reported  as  almost  filling  the  opening  with  stalactitic 
masses.1  In  the  Jerome  district  this  mode  of  occurrence 
is  very  common  ;  indeed,  the  mine  waters  are  especially 
charged  with  the  mineral,  so  that  it  is  found  worth  while 
to  extract  the  copper  by  passing  the  water  containing 
this  mineral  in  solution,  over  scrap  iron.  Fine  stalactites, 
received  from  this  locality,  were  nearly  two  feet  in  length. 
Unfortunately  the  mineral  does  not  keep  well,  and  the 
loss  of  water  of  crystallization  causes  it  to  disintegrate 
and  fall  to  pieces. 

Copiatite,  2Fe203,  sS04,  i8H20 

This  is  an  unusually  rare  basic  sulphate  of  iron.  A 
small  specimen  from  the  Mineral  Hill  district  has  been 
identified  at  the  University  of  Arizona.  It  appears  as 

i  u.  s.  G.  s.,  PP.  NO.  43. 


OXYGEN   SALTS  $1 

small  bright  yellow,   silky  fibers,  and  slightly  foliated 
masses,  not  unlike  orpiment  in  general  appearance. 

Alunite,  KaO,  3A1203  4S03,  6H20 

This  mineral  is  sometimes  known  as  alum  stone.  It 
has  been  reported  as  occurring  in  a  narrow  seam  on  a 
contact  between  shale  and  porphyry  in  the  Ryerson  mine 
at  Morenci.  It  is  further  sometimes  found  associated 
with  pyrite  and  kaolin  in  other  parts  of  the  same  district. 
It  is  described  as  sometimes  quite  clayey  in  appearance 
so  that  it  might  easily  be  mistaken  for  that  mineral.1 

Jarosite 

This  is  usually  a  ocher-yellow,  soft  mineral  having  the 
composition  of  the  hydrous  sulphate  of  iron  and  potash. 
It  has  been  reported  from  the  Vulture  mine  where  it  oc- 
curs associated  with  gold  in  quartz.2 
Emmonsite 

The  composition  of  this  mineral  is  rather  obscure,  but 
it  is  thought  to  be  a  tellurate  of  iron  with  water.  It  has 
been  reported  from  Tombstone  as  occurring  it  thin  yellow- 
ish green  scales.3 

Ettringite 

This  is  a  hydrous  sulphate  of  aluminium  and  calcium. 
It  is  of  very  rare  occurrence.  The  mineral,  however,  has 
been  discovered  in  the  Lucky  Cuss  mine  at  Tombstone 
by  Mr.  W.  F.  Stanton  and  described  and  analyzed  by  A. 
J.  Moses.  It  is  a  white  fibrous  mineral  incrusting  a  sili- 
cate of  lime  and  alumina.4 

1  U.  S.  G.  S.,  PP.   No.  43. 

2  Am.  Jour.  Sci.,  sd  series,  ai,  p.  160. 
8  Dana  :  Text- Book. 

*  Am.  Jour.  Sci.,  sd  series,  45,  p.  489. 


92  THE    MINERALOGY    OF    ARIZONA 

(5)  TUNGSTATES,  MOLYBDATES 

Wolframite,  (Fe,Mn)W04,  and  Huebnerite,  MnW04 
These  rare  and  useful  minerals  have  been  reported  from 
several  localities  in  Arizona.  The  two  minerals  resemble 
each  other  so  closely  and  gradate  one  into  the  other  in  such 
a  manner  that  they  can  be  distinguished  only  with  difficulty 
without  a  chemical  analysis.  The  huebnerite,  however, 
usually  shows  a  peculiar  internal  red  reflection  by  which 
it  can  sometimes  be  distinguished.  The  two  minerals  are 
of  equal  value  in  the  steel  industries.  Wolframite  was 
first  discovered  in  Arizona  in  1896  by  Professor  W.  P. 
Blake,  then  Director  of  the  Arizona  School  of  Mines.  It 
was  described  as  occurring  in  grains  in  quartz  and  asso- 
ciated with  gold  in  the  Arivaca  district.1  Perhaps  the 
most  extensively  worked  deposits  are  those  of  the  Dragoon 
mountains  near  the  Southern  Pacific  railway  station  of 
Dragoon  Summits.  The  mineral  from  this  locality  was 
identified  at  the  Arizona  School  of  mines  in  1898  as 
huebnerite  and  analyses  made  by  the  writer.  The  com- 
position is  represented  in  the  following  table  : 

FeO 2.66 

W03 75.36 

MnO 19.50 

SiO2 1.70 

Undetermined o.  78 

100.00 

The  mineral  occurs  in  extensive  quartz  veins,  perhaps 
of  pegmatitic  origin,  associated  with  small  quantities  of 

i  Kng.  Min.  Jour.,  65,  p.  607. 


OXYGEN  SAWS  93 

fluospar  and  scheelite.  The  excavation  of  the  vein 
material  is  said  to  be  tmremunerative  ;  gathering  the 
float  from  the  canons  and  washes  seem  to  be  more 
profitable.  Several  car-loads  of  this  material  were  re- 
ceived at  the  University  of  Arizona  from  the  owners, 
Messrs.  Stein  and  Boericke,  for  the  purpose  of  concen- 
tration in  the  jigs  of  the  School  of  Mines.  The  concen- 
trates contained  nearly  70  per  cent,  of  tungstic  acid,  while 
the  tailings  assayed  but  0.80  per  cent.  The  price  of  the 
material  thus  concentrated  has  varied  greatly  according 
to  the  demand  ;  the  value  has  fluctuated  from  $80.00  to 
over  $400.00  per  ton. 

Another  tungsten  locality  has  recently  been  opened  up 
about  80  miles  from  Kingman,  in  the  Aquerra  range. 
The  mineral  is  said  to  occur  in  grains  and  in  masses 
/weighing  as  much  as  twenty  pounds.1 

Still  more  recently  the  mineral  has  been  found  in  the 
Whetstone  mountains,  about  12  miles  south  of  Benson. 
This  deposit  is  unlike  any  others  of  this  mineral  yet  de- 
scribed. "The  deposit  is  at  the  base  of  a  steep  rise  in 
granite,  which  is  intrusive  in  a  series  of  metamorphic 
rocks,  including  siliceous  mica,  schist  and  limestone.  The 
wolframite  occurs  near  the  contact  of  the  granite  and 
schist  and  in  a  tongue  of  granite  60  to  70  feet  long  and 
perhaps  half  as  wide  which  runs  out  into  the  schist.  The 
granite  is  very  light  colored,  and  except  in  segregations, 
contains  no  dark  constituents.  A  little  wolframite  is 
found  in  the  quartz  vein,  accompanied  by  small  amounts 
of  mica,  bornite  and  probably  chalcopyrite.  A  more 

1  Mineral  Resources,  1905. 


94  THE    MINERALOGY    OF    ARIZONA 

noteworthy  quantity  of  wolframite  occurs  as  segrega- 
tions in  the  granite. "  l  In  places  the  material  is  said 
to  average  10  per  cent,  tungstic  acid,  the  source  being 
segregations  in  the  granite  very  much  as  biotite  and 
hornblende  are  sometimes  collected  in  irregular  patches. 
The  mineral,  however,  should  not  be  looked  upon  as  an 
original  constituent  of  granite,  but  as  the  result  of  peg- 
matitic  action.  Samples  from  this  locality  have  been 
analyzed  in  the  laboratory  of  the  University  of  Arizona, 
by  Mr.  J.  M.  Ruthrauff.  His  results  are  given  in  the 
table  below. 

Per  cent. 

FeO    5.15 

WOS 74. 20 

MnO 18.09 

SiO2 1.95 


Total 99-39 

Deposits  are  further  found  in  Sonora,  Mexico,  so  it 
would  seem  that  the  zone  in  which  the  mineral  occurs  is 
of  considerable  extent. 

Scheelite,  CaW04 

This  is  the  calcium  tungstate  and  occurs  as  a  very 
heavy  light  yellow  or  amber  colored  mineral  in  the  same 
kinds  of  formation  as  wolframite.  As  mentioned  above  it 
is  found  in  small  grains  associated  with  wolframite  in  the 
Dragoon  mountains.  It  is  further  found  as  a  microscopic 
border  about  the  wolframite  grains  in  the  whetstone 
mountains.2  It  is  also  found  in  the  Old  Hat  district  in 

1  U.  S.  G.  S.,  Bui.  No.  380,  p.  164. 
*  U.  S.  G.  S.,  Bui.  No.  380. 


OXYGEN   SAI/TS  95 

the  Catalina  mountains,  where  it  is  described  as  occurring 
in  friable  masses  of  light  brown.1 

Wulfenite,  PbMoO, 

Chemically  this  mineral  is  the  molybdate  of  lead.  It 
is  usually  found  in  thin  tabular  tetragonal  crystals  vary- 
ing in  color  from  nearly  colorless  to  deep  red  or  orange. 
In  Arizona  the  deep  orange  varieties  are,  perhaps,  the 
most  common.  The  mineral  is  found  as  incrustations, 
implanted  crystals  and  as  massive  modifications  sometimes 
filling,  together  with  considerable  siliceous  matter,  rather 
large  veinlets.  It  is  almost  always  associated  with  vana- 
dinite  and  other  minerals  of  lead  and  vanadium.  It  is 
abundant  in  the  Castle  Dome  district,  the  Mammoth 
mine  near  Oracle,  the  Old  Yuma  mine  in  the  Tucson 
mountains  and  many  other  localities  where  it  is  nearly 
always  found  in  quartz  veins  associated  with  gold  or 
silver  ores.  Interesting  samples  of  this  mineral  have 
been  received  at  the  University  consisting  of  very  intimate 
association  of  quartz  and  wulfenite.  The  sections  for 
microscopic  study  have  been  made  of  these,  and  in  nearly 
all  cases  it  has  been  found  that  the  silica  fills  up  the 
interstices  between  the  crystals  of  wulfenite  showing  that 
the  silicification  took  place  later  than  the  deposition  of 
the  molybdate. 

Molybdite 

Molybdite,  or  as  it  is  sometimes  called,  molybdic  ocher, 
is  a  pulverulent  yellow  mineral,  occurring  as  incrustations 
and  tufts  of  small  fibers  in  minute  cavities  and  cracks  in 

1  W.  P.  Blake  :  Rep.  to  Gov.,  1909. 


96  THE    MIN£RAI/)GY    OF    ARIZONA 

the  vein  material.  Its  intimate  association  with  molyb- 
denite or  the  sulphide,  shows  without  much  doubt  that 
it  has  resulted  from  the  latter  through  oxidation  and 
other  chemical  changes.  Until  recently  it  has  been  con- 
sidered as  the  trioxide  of  molybdenum,  but  the  investi- 
gations of  Mr.  Schaller1  has  shown  it  to  be  a  hydrated 
ferric  molybdate.  Investigations  carried  on  in  the  Uni- 
versity of  Arizona  further  show  that  the  Arizona  speci- 
mens are  also  a  ferric  molybdate  instead  of  the  oxide.2 
In  Arizona  the  mineral  is  found  in  white  milky  quartz, 
associated  with  molybdenite  and  limonite  in  the  Santa 
Rita  mountains.  The  composition  was  found  on  chemi- 
cal analysis  to  be  as  follows : 

Water 17.35 

Fe2O3 21.83 

MoOs 60.80 

These  figures  resulted  after  deducting  the  insoluble 
residue,  which  consisted  of  pure  quartz,  and  recalculating 
the  analysis.  The  formula  deduced  from  the  above  fig- 
ures is  Fe2(MoO4)37H2O.  Mr.  Schaller's  results  give 
7j4  molecules  of  water  of  crystallization. 

1  Am.  Jour.  Sci.,  4th  series,  23,  297. 

2  Guild  :  Am.  Jour.  Sci.,  4th  series,  23,  455. 


VII.  NEW  MINERALS  DISCOVERED  IN  ARIZONA 


Coronadite 

This  is  a  new  mineral  recently  discovered  by  Dr.  Hil- 
lebrand.  Analysis  by  Dr.  Hillebrand  show  it  to  be  a  man- 
ganite  of  lead.  It  contains  56.13  per  cent,  of  manganese 
dioxide  and  26.48  per  cent,  of  lead  oxide.  It  is  described 
as  a  dark  metallic  mineral  of  fibrous  structure  and  altering 
to  limonite.  It  is  very  similar  to  psilomelane  in  appear- 
ance. It  was  discovered  in  the  Coronado  vein  in  the 
Clifton-Morenci  district,  and  at  present  is  the  only 
known  locality.1 

Morencite 

This  is  another  new  mineral  recently  discovered  in 
the  Morenci  mines.  It  is  described  as  a  brownish  yellow 
silky  fibrous  compound  probably  resulting  from  contact 
conditions  in  lime  shale.  The  mineral  has  been  analyzed 
by  Dr.  Hillebrand  with  the  following  results  :  * 

Per  cen 

Si02 45.74 

A1203 1.98 

Fe203    29.68 

FeO 0.83 

CaO 1.61 

MgO 3.99 

K2O 0.20 

Na2O o.  10 

H2O,  105 8.84 

H2O,  150 0.12 

H2O  Below  redness 4.27 

FeS2    0.66 

P2O5 0.18 

1  U.  S.  G.  S.,  PP.  No.  43. 

2  U.  S.  G.  S.,  PP.  No.  43,  p.  115. 


98  THE    MINERALOGY    OF    ARIZONA 

Copper  Pitch  Ore 

This  is  an  ill  defined  dark  brown  to  black  pitchy  appear- 
ing mineral  of  copper,  found  associated  with  cuprite, 
chrysocolla,  and  other  minerals  of  copper  in  the  Copper 
Queen,  Morenci  and  Globe  districts.  The  mineral  has 
been  investigated  from  time  to  time  but  not  very  conclusive 
results  as  to  its  real  nature  have  been  reached.  Perhaps 
the  most  satisfactory  investigations  are  those  of  Lindgren 
and  Hillebrand  on  samples  from  Clifton.  Hillebrand's 
analysis  gave  the  following  results  : 

Per  cent. 

CuO    : 28.6 

ZnO   8.4 

MnO2 21.2 

Fe, Al  and  P 4.0 

Insoluble 22.8 

Ignition 13. 7 

From  the  above  preliminary  analysis  of  Dr.  Hillebrand 
the  mineral  would  seem  to  be  some  compound  of  manga- 
nese and  copper.1 

Quite  probably,  however,  this  pitch  mineral  does  not 
always  have  the  same  composition.  Professor  Koenig 
had  examined  some  of  the  same  or  similar  material  from 
Bisbee.  As  the  results  of  his  analysis  he  considers  the 
mineral  to  be  a  basic  salt  of  orthosilico-carbonic  acid. 
He  has  named  the  mineral  Melanochalcite.2 

1  U.  S.  G.  S.,  PP.  No.  43,  P.  H4. 

2  Am.  Jour.  Sci.,  14,  p.  404. 


NEW   MINERALS  DISCOVERED  IN  ARIZONA  99 

Arizonite 

This  is  a  ferric  metatitanite  and  has  very  recently  been 
discovered  on  the  claims  of  Mr.  A.  G.  Aim,  25  miles 
from  Hackberry,  Arizona.  It  is  associated  with  Gado- 
linite.  Mr.  Palmer  found  the  composition  to  be  as 
follows:1 

Per  cent. 

FeO 0.70 

Fe,03   38.38 

TiO2   58.26 

H20 0.18 

HSO,  115 1.02 

1  Palmer  :  Am.  Jour.  Sci.  28,  p.  353. 


INDEX 


PAGE 

Actinolite 58 

Agate 36 

Alabandite 27 

Alunite 91 

Amethyst 41 

Amphibole 58 

Andalusite  .   .       64 

Anglesite 84 

Apatite 73 

Aragonite 48 

Argentite 24 

Arizonite     99 

Arsenic 8 

Asbestos 69 

Atacamite 35 

Augite ....  58 

Aurichalcite 56 

Azurite 55 

Barite 83 

Biotite 68 

Bornite 28 

Bournonite ...  31 

Brochantite 86 

Calamine 66 

Calcite 46 

Caliche 48 

Cement  clay 71 

Cerargyrite 33 

Cerussite 55 

Chalcantite 90 

Chalcedony 36 

Chalcocite 25 

Chalcophyllite  ...       86 

Chalcopyrite 28 

Chalcotrichite 42 

Chrysocolla 73 

Chrysolite 61 

Chrysoprase 40 


PAGE 

Chrysotile 69 

Cinnabar 27 

Clay 70 

Cobalt  bloom 79 

Cobaltite 30 

Cohenite 30 

Colemanite 82 

Connellite 86 

Copiapite 90 

Copper ii 

Copper  glance 25 

Copper  pitch  ore 98 

Coronadite 97 

Covellite  .   .   . 28 

Crocoite 85 

Cuprite 42 

Cuprodescloizite 76 

Cyanite 64 

Dannemorite ....       59 

Descloizite 76 

Diamond 5 

Diatomaceous  earth 37 

Dolomite 47 

Domeykite 24 

Dioptase  ...       62 

Dumortierite 67 

Ecdemite 74 

Embolite 33 

Emmonsite 91 

Epidote 64 

Epsomite 89 

Erythrite 79 

Ettringite 91 

Feldspar 56 

Flint 4i 

Fluorite 34 

Footeite 35 


IO2 


INDEX 


PAGE 

Gadolinite 65 

Galena 25 

Garnet 59 

Gehardite 82 

Glauberite 83 

Gold 9 

Goslarite 89 

Graphite 8 

Graphitic  clay 71 

Gypsum 87 

Halite 33 

Heavy  spar 83 

Hematite 44 

Hessite 35 

Hornblende 58 

Huebnerite 92 

Hyalite 42 

Ice 43 

lodobromite 34 

lodyrite 34 

Iron 14 

Iron  pyrites    . 29 

Jasper 40 

Jarosite 91 

Kaolin 70 

I^eadhillite 87 

I,ettsomite 73 

I^ibethenite     76 

limestone 46 

I<imonite 45 

I«inarite 89 

Magnetite 45 

Malachite 55 

Marble 48 

Meteoric  iron 14 

Mexican  onyx 48 

Mica 68 

Microcline 57 

Mimetite 74 

Mirabilite 87 


PAGE 

Molybdenite 23 

Molybdite 95 

Morencite 97 

Muscovite 68 

Nitre 81 

Nitrocalcite 81 

Olivine 61 

Onyx,  Mexican     48 

Opal 42 

Orthoclase 56 

Peridot     61 

Petrified  wood 38 

Plagioclase 57 

Platinum .   .  14 

Polybasite 32 

Proustite 31 

Pyrargyrite 31 

Pyrite 29 

Pyrolusite 45 

Pyrope 60 

Pyroxene 58 

Quartz 36 

Rhodochrosite 55 

Ruby,  Arizona 60 

Scheelite 94 

Schreibersite 30 

Semi-opal 42 

Sericite 68 

Serpentine 68 

Siderite     54 

Silver     n 

Silver  glance 24 

Spangolite 85 

Specular  iron 44 

Sphalerite 26 

Stromeyerite 26 

Sulphur 8 


INDEX 


103 


Talc 69 

Tenorite 43 

Tetradymite 23 

Tetrahedrite 31 

Thenardite 83 

Topaz 63 

Tourmaline 66 

Tremolite 58 

Turquoise 79 


Vanadinite 74 

Vauquelinite 85 

Vesuvianite 63 

Willemite 62 

Wolframite 92 

Wollastonite 62 

Wulfenite 95 

Zircon 63 


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